Hemophilia Disease Information

Hemophilia is an inherited bleeding disorder. Blood contains many proteins, called clotting factors, which work to stop bleeding. People with hemophilia have a low level or absence of one of these clotting factors in their blood.

The lack of clotting factor causes people with hemophilia to bleed for longer periods of time than people whose blood factor levels are normal. People with hemophilia do not bleed faster than other people, and will not bleed to death from a minor cut or injury. The main problem for people with hemophilia is bleeding internally, mainly into muscles and joints.


What is the difference between hemophilia A and hemophilia B?

There are two types of hemophilia: hemophilia A (sometimes called classical hemophilia) and hemophilia B (sometimes called Christmas disease). Both are caused by a low level or absence of one of the proteins in the blood (called factors) that control bleeding. Hemophilia A is caused by a deficiency of factor VIII, and hemophilia B is caused by a deficiency of factor IX.

There is no difference between the two types of hemophilia, except that hemophilia B is about five times less common than hemophilia A.


Are there other types of bleeding disorders?

Yes, there are several other factor deficiencies that also cause abnormal bleeding. These include deficiencies in factors I, II, V, VII, X, XI, XIII and von Willebrand factor. The most severe forms of these deficiencies are even rarer than hemophilia A and B.

von Willebrand disease
Other bleeding disorders


How does a person get hemophilia?

Hemophilia is a genetic disorder, which is usually inherited. It cannot be caught or transmitted except through inheritance. The hemophilia gene is passed down from a parent to a child.

About one third of new cases are caused by a newmutation of the gene in the mother or the child. In these cases, there is no previous history of hemophilia in the family.


Is hemophilia lifelong?

A person born with hemophilia will have it for life. The level of factor VIII or IX in his blood usually stays the same throughout his life.


Does hemophilia only affect men?

The most severe forms of hemophilia affect almost only males. Females can be seriously affected only if the father has hemophilia and the mother is a carrier. This is extremely rare. However, many women who are carriers have symptoms of mild hemophilia.


How is hemophilia inherited?

The hemophilia gene is passed down from a parent to a child.

When the father has hemophilia but the mother does not, none of the sons will have hemophilia. All of the daughters will carry the hemophilia gene.

The genes for hemophilia A and B are on the X chromosome. The chromosomes that determine a person’s sex are called X and Y. Men have an X and a Y chromosome and women have two X chromosomes. Since men have only one X chromosome, if they inherit the hemophilia gene, they will have hemophilia. Because women have two X chromosomes, if one X chromosome has the hemophilia gene, the other X chromosome makes up for it.

Women who have the hemophilia gene are called carriers, and they can pass it on to their children. When the mother is a carrier and the father is normal, for each child there is a 50% chance that a son will have hemophilia and a 50% chance that a daughter will carry the gene. Father with hemophilia Mother carrying hemophilia gene

Are there any precautions a carrier should take if she becomes pregnant?

It is important that a carrier’s hematologist is involved in the supervision of the pregnancy and that there is some liaison with the obstetrician before delivery. It is not necessary to perform prenatal diagnosis just for management of the pregnancy. This is only done if termination of a pregnancy is being considered.

The factor VIII level (but not factor IX) tends to rise during pregnancy but it should bechecked sometime in the last couple of months of pregnancy.

A normal vaginal delivery is perfectly acceptable even if the fetus is known to be male and at risk of hemophilia. Epidural anesthesia does not usually present a problem and is generally permissible if the patient’s factor level is 40 percent or more. A cord blood sample after delivery will be used to check if a male baby has hemophilia.


What is acquired hemophilia?

In rare cases, a person can develop hemophilia later in life. The majority of cases involve middle-aged or elderly people, or young women who have recently given birth or are in the later stages of pregnancy.

Acquired hemophilia is usually caused by the development of antibodies to factor VIII (the body’s immune system destroys its own naturally produced factor VIII).

This condition often resolves with appropriate treatment, which typically involves a combination of steroid treatment and the drug cyclophosphamide.


How common is hemophilia?

Hemophilia is quite rare. About 1 in 10,000 people is born with hemophilia A. About 1 in 50,000 people is born with hemophilia B.


How serious is hemophilia?

The severity of hemophilia is determined by the level of clotting activity of factor VIII or factor IX in the blood. There are three levels of severity: mild, moderate, and severe. The following table shows the range of factor VIII and factor IX activity:
Level
Percentage of normal factor activity in blood
Number of international units (IU) per millilitre (ml) of whole blood

normal range
50%-150%
0.50–1.5 IU

mild hemophilia
5%-40%
0.05–0.40 IU

moderate hemophilia
1%-5%
0.01–0.05 IU

severe hemophilia
less than 1%
less than 0.01 IU


People with severe hemophilia usually bleed frequently into their muscles or joints. They may bleed one to two times per week. Bleeding is often spontaneous, which means the bleeding just happens with no obvious cause.

People with moderate hemophilia bleed less frequently, usually after an injury, perhaps once a month. Cases of hemophilia vary, however, and a person with moderate hemophilia can bleed spontaneously.

People with mild hemophilia usually bleed only as a result of surgery or major injury. They may never have a bleeding problem.


What are the signs of hemophilia?

The signs of hemophilia A and B are the same.
Big bruises
Bleeding into muscles and joints, especially the knees, elbow, and ankles
Spontaneous bleeding (sudden bleeding inside the body for no clear reason)
Bleeding for a long time after getting a cut, removing a tooth, or having surgery
Serious internal bleeding into vital organs, most commonly after a serious trauma


How is hemophilia diagnosed?

Hemophilia is diagnosed by taking a blood sample and measuring the level of factor activity in the blood. Hemophilia A is diagnosed by testing the level of factor VIII coagulation activity in the blood. Hemophilia B is diagnosed by measuring the level of factor IX activity.

If the mother is a carrier, testing can be done before a baby is born. Prenatal diagnosis can be done at 9 to 11 weeks by chorionic villus sampling (CVS) or by fetal blood sampling at a later stage (18 or more weeks).

These tests can be done at a hemophilia treatment centre. A list of treatment centres around the world is accessible from the WFH web site. Click on Passport to search the directory.


Where do bleeds occur?

Most bleeding in hemophilia occurs internally, into the joints or muscles.

The joints that are most often affected are the knee, ankle, and elbow. Repeated bleeding without prompt treatment can damage the cartilage and the bone in a joint, leading to chronic arthritis and disability.

The most serious muscle bleeds are the iliopsoas muscle (the front of the groin area). the forearm, and the calf.

Some bleeds can be life-threatening and require immediate treatment. These include bleeds in the head, throat, gut, or iliopsoas.


How is hemophilia treated?

Hemophilia is treated by replacing the missing clotting factor in the blood. This is done by injecting a product that contains the needed factor into a vein. Bleeding stops when enough clotting factor reaches the bleeding site. It is very important that treatment is given as quickly as possible to prevent long-term damage.

With an adequate quantity of treatment products and proper care, people with hemophilia can live perfectly healthy lives.

Clotting factors are found in the following blood products in order of decreasing concentration:
factor concentrates
cryoprecipitate
plasma
whole blood

Factor concentrates are the treatment of choice for hemophilia. They can be made from human blood (called plasma-derived products) or manufactured using genetically engineered cells that carry a human factor gene (called recombinant products). Factor concentrates are made in sophisticated manufacturing facilities. All commercially prepared factor concentrates are treated to remove or inactivate blood-borne viruses.

People with mild hemophilia A sometimes use desmopressin (also called DDAVP), a synthetic hormone that stimulates the release of factor VIII.

Cryoprecipitate is derived from blood and contains a moderately high concentration of factor VIII (but not IX) clotting factor. It is effective for joint and muscle bleeds, but is less safe from viral contamination than concentrates and is harder to store and administer. Cryoprecipitate can be made at local blood collection facilities.

In fresh plasma the red cells have been removed, leaving the blood proteins including the clotting factors. It is less effective than cryoprecipitate for the treatment of hemophilia A because the factor VIII is less concentrated. Large volumes of plasma must be transfused. This can cause circulatory overload.

The life of the clotting factors is preserved by making a product called fresh frozen plasma (FFP). FFP is still the only product available for treatment of hemophilia A and B in some countries.

There are considerable drawbacks to the use of whole blood in the treatment of hemophilia. First, it must be fresh because the activity of the clotting factors in the drawn blood decreases quickly with time. Second, the red cells it contains must, of course, be compatible with those of the recipient. Third, it takes a large volume of whole blood to stop a bleed and this volume may overload the circulation and cause the heart to fail.


Are bruises dangerous?

Bruises are very common in children with hemophilia. A bruise is not usually cause for alarm unless it is on the person’s head or neck, the person has a hard time moving, the bruise hurts, the lump in the bruise gets larger or does not go away, or there is numbness, or a tingling feeling along with the bruising. If any of these symptoms are experienced, a physician or local hemophilia treatment centre should be consulted.

Should people with hemophilia avoid aspirin?

People with hemophilia should not take aspirin (ASA or acetylsalicyclic acid), or anything containing aspirin, because it interferes with the stickiness of the blood platelets and adds to problems with bleeding.

Paracetamol (acetominophen) is a perfectly safe alternative to aspirin to relieve pain, for example, headaches.


Should people with hemophilia exercise and play sports?

Some people with hemophilia do not exercise because they think it may cause bleeds, but exercise can actually help prevent bleeds. Strong muscles help protect someone who has hemophilia from spontaneous bleeds and joint damage.

Sport is an important activity for young people. It not only helps build their muscles, it helps them develop mental concentration and coordination, and learn about being part of a team. However, some sports are riskier than others, and the benefits must be weighed against the risks. The severity of a person’s hemophilia should also be considered when choosing a sport. Sports like swimming, badminton, cycling, and walking are sports that most people with hemophilia can safely participate in, whilst sports like American football, rugby, and boxing are not recommended for people with hemophilia.

Go for It , a guide to sport for people with hemophilia, can be ordered online using the WFH order form.


What are inhibitors?

Inhibitors are antibodies to factor VIII or factor IX made by the body’s immune system that attack and destroy the factor VIII and IX proteins in clotting factor concentrates, making treatment ineffective. They appear almost exclusively in patients with severe hemophilia. There is some controversy over the precise incidence (number of new cases) of inhibitor development, but it is generally accepted that between 10 and 30 percent of people with severe hemophilia A will develop inhibitors at some stage. By contrast, inhibitor development in hemophilia B is very rare indeed, and seen in 1 to 3 percent of subjects. Most inhibitors emerge after relatively few treatments. In general, the more treatments a person has had without developing inhibitors, the less likely he is to develop an inhibitor.

Treatments exist that can sometimes eliminate inhibitors. In other cases, they disappear naturally. In other cases, they continue for many years.


What is prophylaxis?

Prophylaxis is the regular use of clotting factor concentrates to prevent bleeds before they start. Injections of clotting factor are given one, two or three times a week to maintain a constant level of factor VIII or IX in the bloodstream. Prophylaxis can help reduce or prevent joint damage. In countries with access to adequate quantities of clotting factor concentrates, this is becoming the normal mode of treatment for younger patients, and can be started when the veins are well developed (usually between the ages of two and four years).


What is a venous access device (port-a-cath)?

A port-a-cath, or implantable venous access device (IVAD), is implanted under the skin, usually in the upper chest but there are models which can be inserted into the arm. It has a small metal reservoir with a rubber diaphragm which is connected to a catheter which is then threaded into a large vein in the chest or arm. The entire device is surgically implanted under the skin so there is no catheter that hangs out of the body. The device provides ready access to a vein for administering medications and fluids intravenously. It can also be used for drawing blood samples.

The device is accessed by inserting a special needle through the skin and into the rubber diaphragm of the reservoir. The medication or fluid is injected into the device and it flows through the catheter into the vein.

These devices have made prophylaxis in hemophilia much easier for families because the problems of "finding a vein" for infusion two to three times a week are eliminated. However, there are risks involved with their use, the most worrisome being that of infection. Studies differ but some show an infection rate as high as 50 percent. These infections can usually be treated with intravenous antibiotics but sometimes the device must be removed. Also, there are other studies that show a risk of clots forming at the tip of the catheter. Still, many families have chosen to use the device in spite of the risk because of the benefits. Like any other procedure, one must weigh the risks and benefits.


Is there a cure for hemophilia?

There is no cure for hemophilia yet but gene therapy remains an exciting possibility and holds out the prospect of a partial or complete cure for hemophilia. There are many technical obstacles to overcome, but it is encouraging to see the research efforts currently underway.


What is the life expectancy of someone with hemophilia?

The life expectancy of someone with hemophilia varies depending on whether they receive proper treatment. Without adequate treatment, many people with hemophilia die before they reach adulthood. However, with proper treatment, life expectancy for people with hemophilia is about 10 years less than that of males without hemophilia, and children can look forward to a normal life expectancy.

Hemochromatosis Disease Information

Hemochromatosis is the most common form of iron overload disease. Primary hemochromatosis, also called hereditary hemochromatosis, is an inherited disease. Secondary hemochromatosis is caused by anemia, alcoholism, and other disorders.

Juvenile hemochromatosis and neonatal hemochromatosis are two additional forms of the disease. Juvenile hemochromatosis leads to severe iron overload and liver and heart disease in adolescents and young adults between the ages of 15 and 30. The neonatal form causes rapid iron buildup in a baby’s liver that can lead to death.

Excess iron is stored in body tissues, specifically the liver, heart, and pancreas.

Hemochromatosis causes the body to absorb and store too much iron. The extra iron builds up in the body’s organs and damages them. Without treatment, the disease can cause the liver, heart, and pancreas to fail.

Iron is an essential nutrient found in many foods. The greatest amount is found in red meat and iron-fortified breads and cereals. In the body, iron becomes part of hemoglobin, a molecule in the blood that transports oxygen from the lungs to all body tissues.

Healthy people usually absorb about 10 percent of the iron contained in the food they eat, which meets normal dietary requirements. People with hemochromatosis absorb up to 30 percent of iron. Over time, they absorb and retain between five to 20 times more iron than the body needs.

Because the body has no natural way to rid itself of the excess iron, it is stored in body tissues, specifically the liver, heart, and pancreas.

What causes hemochromatosis?

Hereditary hemochromatosis is mainly caused by a defect in a gene called HFE, which helps regulate the amount of iron absorbed from food. The two known mutations of HFE are C282Y and H63D. C282Y is the most important. In people who inherit C282Y from both parents, the body absorbs too much iron and hemochromatosis can result. Those who inherit the defective gene from only one parent are carriers for the disease but usually do not develop it; however, they still may have higher than average iron absorption. Neither juvenile hemochromatosis nor neonatal hemochromatosis are caused by an HFE defect. Juvenile and neonatal hemochromatosis are caused by a mutation in a gene called hemojuvelin.

What are the risk factors of hemochromatosis?

Hereditary hemochromatosis is one of the most common genetic disorders in the United States. It most often affects Caucasians of Northern European descent, although other ethnic groups are also affected. About five people out of 1,000—0.5 percent—of the U.S. Caucasian population carry two copies of the hemochromatosis gene and are susceptible to developing the disease. One out of every 8 to 12 people is a carrier of one abnormal gene. Hemochromatosis is less common in African Americans, Asian Americans, Hispanics/Latinos, and American Indians.

Although both men and women can inherit the gene defect, men are more likely than women to be diagnosed with hereditary hemochromatosis at a younger age. On average, men develop symptoms and are diagnosed between 30 to 50 years of age. For women, the average age of diagnosis is about 50.

What are the symptoms of hemochromatosis?

Joint pain is the most common complaint of people with hemochromatosis. Other common symptoms include fatigue, lack of energy, abdominal pain, loss of sex drive, and heart problems. However, many people have no symptoms when they are diagnosed.

If the disease is not detected and treated early, iron may accumulate in body tissues and eventually lead to serious problems such as
arthritis
liver disease, including an enlarged liver, cirrhosis, cancer, and liver failure
damage to the pancreas, possibly causing diabetes
heart abnormalities, such as irregular heart rhythms or congestive heart failure
impotence
early menopause
abnormal pigmentation of the skin, making it look gray or bronze
thyroid deficiency
damage to the adrenal glands

How is hemochromatosis diagnosed?

A thorough medical history, physical examination, and routine blood tests help rule out other conditions that could be causing the symptoms. This information often provides helpful clues, such as a family history of arthritis or unexplained liver disease.

Blood tests can determine whether the amount of iron stored in the body is too high. The transferrin saturation test reveals how much iron is bound to the protein that carries iron in the blood. Transferrin saturation values higher than 45 percent are considered too high.

The total iron binding capacity test measures how well your blood can transport iron, and the serum ferritin test shows the level of iron in the liver. If either of these tests shows higher than normal levels of iron in the body, doctors can order a special blood test to detect the HFE mutation, which will confirm the diagnosis. If the mutation is not present, hereditary hemochromatosis is not the reason for the iron buildup and the doctor will look for other causes.

A liver biopsy may be needed, in which case a tiny piece of liver tissue is removed and examined with a microscope. The biopsy will show how much iron has accumulated in the liver and whether the liver is damaged.

Hemochromatosis is considered rare and doctors may not think to test for it. Thus, the disease is often not diagnosed or treated. The initial symptoms can be diverse, vague, and mimic the symptoms of many other diseases. The doctors also may focus on the conditions caused by hemochromatosis—arthritis, liver disease, heart disease, or diabetes—rather than on the underlying iron overload. However, if the iron overload caused by hemochromatosis is diagnosed and treated before organ damage has occurred, a person can live a normal, healthy life.

Hemochromatosis is usually treated by a specialist in liver disorders called a hepatologist, a specialist in digestive disorders called a gastroenterologist, or a specialist in blood disorders called a hematologist. Because of the other problems associated with hemochromatosis, other specialists may be involved in treatment, such as an endocrinologist, cardiologist, or rheumatologist. Internists or family practitioners can also treat the disease.

How is hemochromatosis treated?

Treatment is simple, inexpensive, and safe. The first step is to rid the body of excess iron. This process is called phlebotomy, which means removing blood the same way it is drawn from donors at blood banks. Based on the severity of the iron overload, a pint of blood will be taken once or twice a week for several months to a year, and occasionally longer. Blood ferritin levels will be tested periodically to monitor iron levels. The goal is to bring blood ferritin levels to the low end of normal and keep them there. Depending on the lab, that means 25 to 50 micrograms of ferritin per liter of serum.

Once iron levels return to normal, maintenance therapy begins, which involves giving a pint of blood every 2 to 4 months for life. Some people may need phlebotomies more often. An annual blood ferritin test will help determine how often blood should be removed. Regular follow-up with a specialist is also necessary.

If treatment begins before organs are damaged, associated conditions—such as liver disease, heart disease, arthritis, and diabetes—can be prevented. The outlook for people who already have these conditions at diagnosis depends on the degree of organ damage. For example, treating hemochromatosis can stop the progression of liver disease in its early stages, which leads to a normal life expectancy. However, if cirrhosis, or scarring of the liver, has developed, the person’s risk of developing liver cancer increases, even if iron stores are reduced to normal levels.

People with complications of hemochromatosis may want to receive treatment from a specialized hemochromatosis center. These centers are located throughout the country. Information is available from the organizations listed under For More Information.

People with hemochromatosis should not take iron or vitamin C supplements. And those who have liver damage should not consume alcoholic beverages or raw seafood because they may further damage the liver.

Treatment cannot cure the conditions associated with established hemochromatosis, but it will help most of them improve. The main exception is arthritis, which does not improve even after excess iron is removed.

How is hemochromatosis tested?

Screening for hemochromatosis—testing people who have no symptoms—is not a routine part of medical care or checkups. However, researchers and public health officials do have some suggestions.

Siblings of people who have hemochromatosis should have their blood tested to see if they have the disease or are carriers.

Parents, children, and other close relatives of people who have the disease should consider being tested.

Doctors should consider testing people who have joint disease, severe and continuing fatigue, heart disease, elevated liver enzymes, impotence, and diabetes because these conditions may result from hemochromatosis.

Since the genetic defect is common and early detection and treatment are so effective, some researchers and education and advocacy groups have suggested that widespread screening for hemochromatosis would be cost-effective and should be conducted. However, a simple, inexpensive, and accurate test for routine screening does not yet exist and the available options have limitations. For example, the genetic test provides a definitive diagnosis, but it is expensive. The blood test for transferrin saturation is widely available and relatively inexpensive, but it may have to be done twice with careful handling to confirm a diagnosis and show that the result is the consequence of iron overload.

Hope through Research

Scientists hope further study of the HFE gene will reveal how the body normally metabolizes iron. They also want to learn how iron injures cells and contributes to organ damage in other diseases, such as alcoholic liver disease, hepatitis C, porphyria cutanea tarda, heart disease, reproductive disorders, cancer, autoimmune hepatitis, diabetes, and joint disease.

Scientists are working to find out why only some patients with HFE mutations develop the disease. In addition, hemochromatosis research includes the following areas:

Genetics. Researchers are examining how the HFE gene normally regulates iron levels and why not everyone with an abnormal pair of genes develops the disease.

Pathogenesis. Scientists are studying how iron injures body cells. Iron is an essential nutrient, but above a certain level it can damage or even kill cells.

Epidemiology. Research is underway to explain why the amounts of iron people normally store in their bodies differ. Research is also being conducted to determine how many people with the defective HFE gene go on to develop symptoms and why some people develop symptoms and others do not.

Screening and testing. Scientists are working to determine at what age testing is most effective, which groups should be tested, and which are the best tests for widespread screening.

The U.S. Government does not endorse or favor any specific commercial product or company. Trade, proprietary, or company names appearing in this document are used only because they are considered necessary in the context of the information provided. If a product is not mentioned, the omission does not mean or imply that the product is unsatisfactory.

For More Information

American Hemochromatosis Society, Inc.
4044 West Lake Mary Boulevard
Unit #104 PMB 416
Lake Mary, FL 32746–2012
Phone: 1–888–655–IRON (4766) or 407–829–4488
Fax: 407–333–1284
Email: mail@americanhs.org
Internet: www.americanhs.org

American Liver Foundation
75 Maiden Lane, Suite 603
New York, NY 10038–4810
Phone: 1–800–GO–LIVER (465–4837), 1–888–443–7872, or 212–668–1000
Fax: 212–483–8179
Email: info@liverfoundation.org
Internet: www.liverfoundation.org

Iron Disorders Institute
2722 Wade Hampton Boulevard, Suite A
Greenville, SC 29615
Phone: 1–888–565–IRON (4766) or 864–292–1175
Fax: 864–292–1878
Email: patientservices@irondisorders.org
Internet: www.irondisorders.org

National Organization for Rare Disorders, Inc.
55 Kenosia Avenue
P.O. Box 1968
Danbury, CT 06813–1968
Phone: 1–800–999–6673 or 203–744–0100
Fax: 203–798–2291
Email: orphan@rarediseases.org
Internet: www.rarediseases.org

The National Digestive Diseases Information Clearinghouse collects resource information about digestive diseases for the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Reference Collection. This database provides titles, abstracts, and availability information for health information and health education resources. The NIDDK Reference Collection is a service of the National Institutes of Health.

You may view the results of the automatic search on hemochromatosis.

If you wish to perform your own search of the database, you may access and search the NIDDK Reference Collection database online.

Gaucher's disease Information

Gaucher's (go-SHAYZ) disease occurs when certain harmful fatty substances build to excessive levels in your liver, spleen, lungs, bone marrow and, less commonly, your brain. This accumulation of fatty material in tissues interferes with the normal functioning of organs, and may cause organ enlargement and bone pain.

Gaucher's disease results from an enzyme deficiency, and sometimes the term "glucocerebrosidase deficiency" is used to describe this condition.

Gaucher's disease is most common in Eastern and Central European (Ashkenazi) Jews. It can occur at any age in life, and affects males and females approximately equally.

Gaucher's disease is named after the French doctor who first described the disease in the 1880s. Treatment for Gaucher's disease may involve enzyme replacement and other therapies.
Symptoms

Signs and symptoms of Gaucher's disease can vary widely from one person to another. Bone pain or a bone fracture is often the first symptom. Gaucher's disease symptoms may include:
Skeletal abnormalities, including thinning of your bones (osteopenia), bone pain and bone fractures
Enlarged liver (hepatomegaly) or spleen (splenomegaly), or both
Anemia, due to fewer healthy red blood cells
Excessive fatigue
A greater susceptibility to bruising, which may mean you have a low blood platelet level (thrombocytopenia)
Cognitive deterioration, including mental retardation or dementia
Yellow spots in your eyes (pingueculae)
Abnormal eye movements
Impaired function of your lungs and kidneys
Brownish coloring of your skin

There are three major types of Gaucher's disease. Classification depends on age at the time of diagnosis, and whether the brain and central nervous system are involved:
Type 1. In this form of the disease, there's no brain involvement. It can occur at any age, although it's most prevalent in adults, with an average age of 20 years old at the time of diagnosis. It's by far the most common type of Gaucher's disease.
Type 2. This form of Gaucher's disease is rare and occurs in infants with severe signs and symptoms, such as liver and spleen enlargement, developing by 3 months of age. These babies have brain damage that is extensive and progresses rapidly.
Type 3. This form of Gaucher's disease, also rare, occurs in children and adolescents. It tends to be chronic and progresses more slowly than does type 2. Although the brain is affected, brain involvement tends to be relatively mild. Signs and symptoms, such as enlargement of the liver and spleen, vary in intensity.

Types 2 and 3 account for only 5 percent of the cases of Gaucher's disease.
Causes

The cause of Gaucher's disease is a deficit of the enzyme glucocerebrosidase. This enzyme normally breaks down fatty substances (lipids) called glucocerebrosides. When the enzyme is scarce, however, the fatty substances can build up in your brain and other organs, and also within your bone marrow.

Gaucher's disease is passed along in an inheritance pattern called autosomal recessive. Both parents need to be carriers of the Gaucher's genetic mutation in order for their child to develop the condition. But even when both parents are carriers, there's still only a 25 percent chance that the child will develop the disease, compared with a 50 percent chance of their child being an unaffected carrier, and a 25 percent chance of him or her not being a carrier and not having the disease.
Risk factors

If you're of Eastern or Central European (Ashkenazi) Jewish ancestry, and particularly if you have a family history of Gaucher's disease, you have an increased risk of either developing the disease or being a carrier.
When to seek medical advice

If you have any of the signs and symptoms associated with Gaucher's disease, make an appointment with your doctor for an evaluation.

When a family history of Gaucher's disease is present, ask your doctor about having a blood sample withdrawn for genetic testing that can determine if you are a carrier of the genetic defect. Particularly if you're considering having children, you may also be referred to a genetic counselor to evaluate the potential risks to your offspring.
Tests and diagnosis

If your doctor suspects Gaucher's disease or if Gaucher's disease runs in your family, the diagnosis is made by conducting a blood test that evaluates levels of the enzyme associated with the disease.

People with Gaucher's disease have low levels of the enzyme glucocerebrosidase in their bloodstream. If you're a carrier of the gene responsible for Gaucher's — but don't have the disease itself — you'll have an intermediate enzyme level that falls between those of affected people and those who aren't carriers.

If you receive a diagnosis of Gaucher's disease, your doctor may recommend periodic tests to track its progression. These may include imaging tests such as:
Dual energy X-ray absorptiometry (DXA), which uses low-level X-rays to measure bone density, including changes over time
Magnetic resonance imaging (MRI) scans, which use magnetic fields and radio waves to create images, to help your doctor see whether you have an enlarged spleen or liver

Prenatal testing
For pregnant women who are carriers of the Gaucher's gene, doctors may recommend prenatal testing that can determine whether the fetus is at risk of Gaucher's disease. Tests that evaluate cells in the amniotic fluid (amniocentesis) or evaluate tissue from the placenta (chorionic villus sampling) can detect all types of Gaucher's in the fetus.
Complications

People with type 2 Gaucher's disease often develop serious neurological complications, including:
Seizures
Abnormal gait
Swallowing problems

As these problems progress and become more severe, they can become debilitating and lead to death. Children with type 2 disease usually die by the age of 2 years.

Other possible complications include:
Severe swelling (edema) at birth, caused by a buildup of fluid in tissues
Calcification of heart valves, damaging the valves and making it increasingly difficult for them to open fully and function properly
Bone pain, which can become severe and incapacitating and may be associated with fractures
A tendency to bleed, which may result in repeated hemorrhaging in the nostrils or nasal cavities, or bleeding beneath the skin (ecchymosis)

Older people with Gaucher's disease may have an increased likelihood of developing certain types of cancer, particularly multiple myeloma — uncontrolled multiplication of plasma cells.
Treatments and drugs

To treat Gaucher's disease, your doctor may recommend:

Enzyme replacement therapy. This approach replaces the deficient enzyme with synthetic enzymes. These replacement enzymes are administered in an outpatient procedure through a vein (intravenously), typically at two-week intervals at high doses.

Although effectiveness can vary, it's frequently effective in people with type 1 Gaucher's disease and, in some cases, type 3. In many people, enzyme replacement therapy can reduce the enlargement of the liver and spleen, and help to resolve blood abnormalities. Children treated with enzyme therapy often experience a growth spurt and weight gain as skeletal abnormalities are moderated.

This treatment is most effective when started prior to development of significant organ enlargement or bone impairment. It's unclear whether this therapy is effective for the neurological problems of Gaucher's disease. Occasionally, people experience an allergic or hypersensitivity reaction to enzyme treatment, triggering a rash, nausea, diarrhea or abdominal pain.
Bone marrow transplantation. This surgical procedure has been used for severe cases of Gaucher's disease. In this technique, blood-forming cells that have been damaged by Gaucher's are removed and replaced, which can reverse many of Gaucher's signs and symptoms. Because this approach is high-risk, it's performed much less often than is enzyme replacement therapy.
The medication miglustat (Zavesca). The effectiveness of this oral medication in people with Gaucher's disease is still being studied, but it may be capable of interfering with the production of glucocerebrosides in some people with type 1 disease. Diarrhea and weight loss are common side effects.

Prognosis
People with mild cases of Gaucher's disease, particularly those who develop it in adulthood, have normal life expectancies. Children whose illness begins during infancy generally don't live beyond the age of 2 years old.

By Mayo Clinic Staff

Muscular dystrophy Information

Muscular dystrophy (MD) is a genetic disorder that gradually weakens the body's muscles. It's caused by incorrect or missing genetic information that prevents the body from making the proteins it needs to build and maintain healthy muscles.

A child who is diagnosed with MD gradually loses the ability to do things like walk, sit upright, breathe easily, and move the arms and hands. This increasing weakness can lead to other health problems.

There are several major forms of muscular dystrophy, which can affect a child's muscles in different levels of severity. In some cases, MD starts causing muscle problems in infancy, while in others, symptoms don't appear until adulthood.

There is no cure for MD, but researchers are quickly learning more about how to prevent and treat the condition. Doctors are also working on improving muscle and joint function, and slowing muscle deterioration so that kids, teens, and adults with MD can live as actively and independently as possible.
What Are the First Symptoms of Muscular Dystrophy?

Many kids with muscular dystrophy follow a normal pattern of development during their first few years of life.

But in time common symptoms begin to appear. A child who has MD may start to stumble, waddle, have difficulty going up stairs, and toe walk (walk on the toes without the heels hitting the floor). A child may start to struggle to get up from a sitting position or have a hard time pushing things, like a wagon or a tricycle. It is also common for a young child with MD to develop enlarged calf muscles, a condition called calf pseudohypertrophy, as muscle tissue is destroyed and replaced by fat.
How Is Muscular Dystrophy Diagnosed?

When a doctor first suspects that a child has muscular dystrophy, he or she probably will do a physical exam, take a family history, and ask about any problems - particularly those affecting the muscles - that the child might be experiencing.

In addition, the doctor may perform a series of tests to determine what type of MD a child may have and to rule out any other diseases that may be causing a problem. This might include a blood test to measure levels of serum creatine kinase, an enzyme that's released into the bloodstream when muscle fibers are deteriorating. Elevated levels of this enzyme indicate that something is causing muscle damage.

The doctor also may do a blood test to check a child's DNA for gene abnormalities, or a muscle biopsy to examine a muscle tissue sample for patterns of deterioration and abnormal levels of dystrophin, a protein that helps muscle cells keep their shape and length. Without dystrophin, the muscles break down.
Types of Muscular Dystrophy

The different types of muscular dystrophy affect different sets of muscles and result in different degrees of muscle weakness.

Duchenne muscular dystrophy is the most common and the most severe form of the disease. It affects about 1 out of every 3,500 boys. (Girls can carry the gene that causes the disease, but they usually have no symptoms.) This form of MD occurs because of a problem with the gene that makes dystrophin. Without this protein, the muscles break down and a child becomes weaker.

In cases of Duchenne muscular dystrophy, symptoms usually begin to appear around age 5, as the pelvic muscles begin to weaken. Most kids with this form of MD need to use a wheelchair by age 12. Over time, their muscles weaken in the shoulders, back, arms, and legs. Eventually, the respiratory muscles are affected, and a ventilator is required to assist breathing. Kids who have Duchenne muscular dystrophy typically have a life span of about 20 years.

Although most kids with Duchenne muscular dystrophy have average intelligence, about one-third of them experience learning disabilities and a small number of them have mental retardation.

While the incidence of Duchenne is known, it's unclear how common other forms of MD are because the symptoms can vary so widely between individuals. In fact, in some people the symptoms are so mild that the disease goes undiagnosed.

Becker muscular dystrophy is similar to Duchenne, but it is less common and progresses more slowly. This form of MD affects approximately 1 in 30,000 boys. It too is caused by insufficient production of dystrophin.

With this form of MD, symptoms typically begin during the teen years, then follow a pattern similar to Duchenne muscular dystrophy. Muscle weakness first begins in the pelvic muscles, then moves into the shoulders and back. Many children with Becker have a normal life span and can lead long, active lives without the use of a wheelchair.

Myotonic dystrophy, also known as Steinert's disease, is the most common adult form of muscular dystrophy, although half of all cases are diagnosed in people who are younger than 20 years old. It is caused by a portion of a particular gene that is larger than it should be. The symptoms can appear at any time during a child's life.

The main symptoms include muscle weakness, myotonia (in which the muscles have trouble relaxing once they contract), and muscle wasting, where the muscles shrink over time. Kids with myotonic dystrophy also can experience cataracts and heart problems.

Limb-girdle muscular dystrophy affects boys and girls equally. Typically, symptoms begin when kids are between 8 and 15 years old. This form of MD progresses slowly, affecting the pelvic, shoulder, and back muscles. The severity of muscle weakness varies from person to person. Some kids develop only mild weakness while others develop severe disabilities and as adults need a wheelchair to get around.

Facioscapulohumeral muscular dystrophy can affect both boys and girls, and the symptoms usually first appear during the teen years. This form of muscular dystrophy tends to progress slowly.

Muscle weakness first develops in the face, making it difficult for a child to close the eyes, whistle, or puff out the cheeks. The shoulder and back muscles gradually become weak, and kids who are affected have difficulty lifting objects or raising their hands overhead. Over time, the legs and pelvic muscles also may lose strength.

Other types of muscular dystrophy, which are rare, include distal, ocular, oculopharyngeal, and Emery-Dreifuss.
Caring for a Child With Muscular Dystrophy

Though there's no cure for MD yet, doctors are working to improve muscle and joint function, and slow muscle deterioration in kids who are living with the condition.

If your child is diagnosed with muscular dystrophy, a team of medical specialists will work with you and your family. That team will likely include: a neurologist, orthopedist, pulmonologist, physical and occupational therapist, nurse practitioner, cardiologist, registered dietician, and a social worker.

Muscular dystrophy is often degenerative, so kids may pass through different stages as the disease progresses and require different kinds of treatment. During the early stages, physical therapy, joint bracing, and the medication prednisone are often used. During the later stages, doctors may use assistive devices such as:
physical therapy and bracing to improve your child's flexibility
power wheelchairs and scooters to improve your child's mobility
a ventilator to support your child's breathing
robotics to help your child perform routine daily tasks
Physical Therapy and Bracing

Physical therapy can help a child to maintain muscle tone and reduce the severity of joint contractures with exercises that keep the muscles strong and the joints flexible.

A physical therapist also uses bracing to help prevent joint contractures, a stiffening of the muscles near the joints that can make it harder to move and can lock the joints in painful positions. By providing extra support in just the right places, bracing can extend the time that a child with MD can walk independently.
Prednisone

If a child has Duchenne muscular dystrophy, the doctor may prescribe the steroid prednisone to help slow the rate of muscle deterioration. By doing so, a child with muscular dystrophy may be able to walk longer and live a more active life.

There is some debate over the best time to begin treating a child with prednisone, but most doctors prescribe it when a child with MD is 5 or 6 years old, or when the child's strength begins to show a significant decline. Prednisone does have side effects, though. It can cause weight gain, which can put even greater strain on a child's already-weak muscles. It also can cause a loss of bone density and, possibly, lead to fractures. If your doctor prescribes prednisone, he or she will closely monitor your child.
Spinal Fusion

Many children who have the Duchenne and Becker forms of muscular dystrophy develop severe scoliosis - an S- or C-shaped curvature of the spine that develops when the back muscles are too weak to hold the spine erect. Some kids who have severe cases of scoliosis undergo spinal fusion, a surgery that can reduce pain, lessen the severity of the spine curvature so that a child can sit upright and comfortably in a chair, and ensure that the spine curvature doesn't have an effect on the child's breathing. Typically, spinal fusion surgery only requires a short hospital stay.
Respiratory Care

Many kids with muscular dystrophy also have weakened heart and respiratory muscles. As a result, they can't cough out phlegm and sometimes develop respiratory infections that can quickly become serious. Good general health care and regular vaccinations are especially important for children with muscular dystrophy to help prevent these infections.
Assistive Devices

A variety of new technologies are available to create independence and mobility for kids with muscular dystrophy.

Some kids with Duchenne muscular dystrophy may use a manual wheelchair once it becomes difficult to walk. Others go directly to a motorized wheelchair, which can be equipped to meet their needs as muscle deterioration advances.

Robotic technologies also are under development to help kids move their arms and perform activities of daily living.

If your child would benefit from an assistive technological device, it's a good idea to contact your local chapter of the Muscular Dystrophy Association (see the Additional Resources tab for a link to their website) to ask about financial assistance that might be available. In some cases, health insurers cover the cost of these devices.
The Search for a Cure

Researchers are quickly learning more about what causes the genetic disorder that leads to muscular dystrophy, and about possible treatments for the disease. If you'd like to know more about the most current research on muscular dystrophy, contact the local chapter of the Muscular Dystrophy Association, or talk to your child's doctor.

Updated and reviewed by: Alisa Clark, MSN, RN
Date reviewed: August 2005
Originally reviewed by: David Hammond, MD, and Harold Marks, MD

Down syndrome Information

Down syndrome is a chromosomal disorder that includes a combination of birth defects. Affected individuals have some degree of mental retardation, characteristic facial features and, often, heart defects and other health problems. The severity of these problems varies greatly among affected individuals.

How common is Down syndrome?
Down syndrome is one of the most common genetic birth defects, affecting about 1 in 800 babies (1). According to the National Down Syndrome Society, there are approximately 350,000 individuals with Down syndrome in the United States (2).

What causes Down syndrome?
Down syndrome is caused by extra genetic material from chromosome 21. Chromosomes are the structures in cells that contain the genes.

Each person normally has 23 pairs of chromosomes, or 46 in all. An individual inherits one chromosome per pair from the mother's egg and one from the father's sperm. When an egg and sperm cell join together, they normally form a fertilized egg with 46 chromosomes.

Sometimes something goes wrong before fertilization. A developing egg or sperm cell may divide incorrectly, sometimes resulting in an egg or sperm cell with an extra chromosome number 21. When this cell joins with a normal egg or sperm cell, the resulting embryo has 47 chromosomes instead of 46. Down syndrome also is called trisomy 21 because affected individuals have three number 21 chromosomes, instead of two. This type of error in cell division causes about 95 percent of the cases of Down syndrome (3).

Occasionally, before fertilization, a part of chromosome 21 breaks off during cell division and becomes attached to another chromosome in the egg or sperm cell. The resulting embryo may have what is called translocation Down syndrome. Affected individuals have two normal copies of chromosome 21 plus extra chromosome 21 material attached to another chromosome. This type of error in cell division causes about 3 to 4 percent of the cases of Down syndrome (3). In some cases, the parent has a rearrangement of chromosome 21, called a balanced translocation, which does not affect his or her health.

About 1 to 2 percent of individuals with Down syndrome have a form called mosaicism (3). In this form, the error in cell division occurs after fertilization. Affected individuals have some cells with an extra chromosome 21 and others with the normal number.

What health problems might a child or adult with Down syndrome have?
The outlook for individuals with Down syndrome is far brighter than it once was. Most of the health problems associated with Down syndrome can be treated, and life expectancy is now about 55 years (2). Individuals with Down syndrome are more likely than unaffected individuals to have one or more of the following health conditions:
Heart defects. Almost half of babies with Down syndrome have heart defects (3). Some defects are minor and may be treated with medications, while others require surgery. All babies with Down syndrome should be examined by a pediatric cardiologist, a doctor who specializes in heart diseases of children, and have an echocardiogram (a special ultrasound examination of the heart) in the first two months of life so that heart defects can be treated (2, 3).
Intestinal defects. About 12 percent of babies with Down syndrome are born with intestinal malformations that require surgery (3).
Vision problems. More than 60 percent of children with Down syndrome have vision problems, including crossed eyes (esotropia), near- or far-sightedness and cataracts (3). Glasses, surgery or other treatments usually can improve vision. A child with Down syndrome should be examined by a pediatric ophthalmologist (eye doctor) within the first six months of life and have regular vision exams (3).
Hearing loss. About 75 percent of children with Down syndrome have some hearing loss (3). Hearing loss may be due to fluid in the middle ear (which may be temporary), a nerve or both. Babies with Down syndrome should be screened for hearing loss at birth or by 3 months of age. They also should have regular hearing exams so any problems can be treated before they hinder development of language and other skills (3).
Infections. Children with Down syndrome tend to have many colds and ear infections, as well as bronchitis and pneumonia. Children with Down syndrome should receive all the standard childhood immunizations, which help prevent some of these infections.
Thyroid problems, leukemia and seizures (3)
Memory loss. Individuals with Down syndrome are more likely than unaffected individuals to develop Alzheimer's disease (characterized by progressive memory loss, personality changes and other problems). Adults with Down syndrome tend to develop Alzheimer's disease at an earlier age than unaffected individuals. Studies suggest that about 25 percent of adults with Down syndrome over age 35 have symptoms of Alzheimer's disease (2).

Some individuals with Down syndrome may have a number of these problems, while others may have none. The severity of these conditions varies greatly.

What does a child with Down syndrome look like?
A child with Down syndrome may have eyes that slant upward and small ears that may fold over a little at the top. The child's mouth may be small, making the tongue appear large. The nose also may be small, with a flattened nasal bridge. Some babies with Down syndrome have short necks and small hands with short fingers. Having less muscle tone, they may appear somewhat “floppy.”

The child or adult with Down syndrome is often short and has unusual looseness of the joints. Most children with Down syndrome have some, but not all, of these features.

How serious is the mental retardation?
The degree of mental retardation varies widely. Most fall within the mild to moderate range. With proper intervention, few will have severe mental retardation (3). There is no way to predict the mental development of a child with Down syndrome based upon physical features.

What can a child with Down syndrome do?
Children with Down syndrome usually can do most things that any young child can do, such as walking, talking, dressing and being toilet-trained. However, they generally start learning these things later than other children.

The exact age that these developmental milestones will be achieved cannot be predicted. However, early intervention programs beginning in infancy can help these children achieve their developmental milestones sooner.

Can a child with Down syndrome go to school?
Yes. There are special programs beginning in the preschool years to help children with Down syndrome develop skills as fully as possible. Along with benefiting from early intervention and special education, many children are integrated into the regular classroom. Many affected children learn to read and write, and some graduate from high school and go on to post-secondary programs or college. Individuals with Down syndrome participate in diverse childhood activities both at school and in their neighborhoods.

While there are special work programs designed for adults with Down syndrome, many people with the disorder hold regular jobs. Today, an increasing number of adults with Down syndrome live semi-independently in community group homes where they take care of themselves, participate in household chores, develop friendships, partake in leisure activities and work in their communities.

Can Down syndrome be cured or prevented?
There is no cure for Down syndrome, nor is there any way to prevent it. However, some studies suggest that women who have certain variant genes that affect how their bodies metabolize (process) the B vitamin folic acid may be at increased risk for having a baby with Down syndrome (4, 5). If confirmed, this finding may provide yet another reason why all women who might become pregnant should take a daily multivitamin containing 400 micrograms of folic acid (which has been shown to reduce the risk of certain birth defects of the brain and spinal cord).

Does the risk of Down syndrome increase with the mother's age? Yes. The risk of Down syndrome increases from about 1 in 1,250 at age 25, to 1 in 1,000 at age 30, 1 in 400 at age 35, 1 in 100 at age 40 and 1 in 30 at age 45 (6). Women over age 35 have been traditionally considered most likely to have a baby with Down syndrome. However, about 80 percent of babies with Down syndrome are born to women who are under age 35, as younger women have far more babies (2).

What is the risk that parents of a child with Down syndrome will have another affected child?
In general, in each subsequent pregnancy, the chance of having another baby with Down syndrome is 1 percent plus whatever additional risk a mother has, based upon her age (2, 7). If, however, the first child has translocation Down syndrome, the chance of having another child with Down syndrome may be greatly increased.

After birth, the provider takes a blood sample from a baby suspected of having Down syndrome and sends it to a laboratory. The lab examines the chromosomes (called a karyotype) to determine if the baby has Down syndrome and what genetic form of Down syndrome the baby has. This information is important in determining the risk in future pregnancies. The doctor may refer parents to a genetic counselor who can explain the results of chromosomal tests in detail, including what the recurrence risks may be in another pregnancy.

Can Down syndrome be diagnosed before the child is born?
Yes. The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women be offered a screening test for Down syndrome, regardless of the woman's age. Screening may consist of a maternal blood test done in the first trimester (at 11 to 13 weeks of pregnancy), along with a special ultrasound examination of the back of the baby's neck (called nuchal translucency), or a maternal blood test done in the second trimester (at 15 to 20 weeks) (8). A screening test helps identify pregnancies that are at higher-than-average risk of Down syndrome. However, a screening test cannot diagnose Down syndrome or other birth defects.

Women who have an abnormal screening test result are offered a diagnostic test, such as amniocentesis or chorionic villus sampling (CVS). These tests are highly accurate at diagnosing, or more likely, ruling out Down syndrome.

ACOG also recommends that pregnant women of all ages have the option of bypassing the screening test and choosing a diagnostic test for Down syndrome instead (8). Until recently, only women over age 35 and others considered at increased risk for having a baby with Down syndrome were offered diagnostic testing because amniocentesis and CVS pose a very small risk of miscarriage.

Most parents-to-be receive reassuring news from a screening or diagnostic test for Down syndrome. However, if a prenatal diagnostic test shows that the baby has Down syndrome, parents have an opportunity to prepare medically, emotionally and financially for the birth of a child with special needs, such as arranging for delivery in a medically appropriate setting.

Can people with Down syndrome have children?
Some people with Down syndrome marry. With rare exceptions, men with Down syndrome cannot father a child (3). In any pregnancy, a woman with Down syndrome has a 50-50 chance of conceiving a child with Down syndrome, but many affected fetuses are miscarried.

Is the March of Dimes conducting research on Down syndrome?
Some March of Dimes grantees are investigating why errors in chromosome division occur, in the hope of someday preventing Down syndrome and other birth defects caused by abnormalities in the number or structure of chromosomes. Other grantees are investigating the role of specific genes in causing the brain abnormalities associated with Down syndrome, with the goal of treating the mental retardation associated with the disorder. An international team of scientists has mapped all the genes of chromosome 21. This information eventually may pave the way for treatment of many features of this disorder.

Where can families affected by Down syndrome get additional information?
There are organizations across the country that provide information and support for families with children affected by Down syndrome. Two are:

National Down Syndrome Society
666 Broadway
New York, NY 10012
(800) 221-4602 or (212) 460-9330

National Down Syndrome Congress 1370 Center Drive, Suite 102
Atlanta, GA 30338
800 (232)-NDSC or (770) 604-9500

References

Centers for Disease Control and Prevention (CDC). Birth Defects: Frequently Asked Questions. Updated 12/12/06.

National Down Syndrome Society. Information Topics. Accessed 1/11/07..

American Academy of Pediatrics Committee on Genetics. Health Supervision for Children with Down Syndrome. Pediatrics, volume 107, number 2, February 2001, pages 442-449.

O'Leary, V.B., et al. MTRR and MTHFR Polymorphism: Link to Down Syndrome? American Journal of Medical Genetics, January 15, 2002, volume 107, number 2, pages 151-155.

Scala, I., et al. Analysis of Seven Maternal Polymorphisms of Genes Involved in Homocysteine/Folate Metabolism and Risk of Down Syndrome. Genetics in Medicine, volume 8, number 7, July 2006, pages 409-416.

American College of Obstetricians and Gynecologists (ACOG). Your Pregnancy and Birth, 4th Edition. ACOG, Washington, DC, 2005.

National Institute of Child Health and Human Development (NICHD). Facts About Down Syndrome. Last updated 8/18/06.

American College of Obstetricians and Gynecologists (ACOG). Screening for Fetal Chromosomal Abnormalities. ACOG Practice Bulletin, number 77, January 2007.

Prenatal tests Information

Every parent-to-be hopes for a healthy baby, but it can be hard not to worry: What if the baby has a serious or untreatable health problem? What would I do? Would it be my fault?

Concerns like these are completely natural. Fortunately, though, a wide array of tests for pregnant women can help to reassure them and keep them informed throughout their pregnancies.

Prenatal tests can help identify — and sometimes treat — health problems that could endanger both you and your unborn child. However, they do have limitations. As an expectant parent, it's important to educate yourself about these tests and to think about what you would do if a health problem is detected in either you or your baby.
Why Are Prenatal Tests Performed?

Prenatal tests can identify several different things:
treatable health problems in the mother that can affect the baby's health
characteristics of the baby, including size, sex, age, and placement in the uterus
the chance that a baby has certain congenital, genetic, or chromosomal problems
certain types of fetal abnormalities, including heart problems

The last two items on this list may seem the same, but there's a key difference. Some prenatal tests are screening tests and only reveal the possibility of a problem. Other prenatal tests are diagnostic, which means they can determine — with a fair degree of certainty — whether a fetus has a specific problem. In the interest of making the more specific determination, the screening test may be followed by a diagnostic test.

Prenatal testing is further complicated by the fact that approximately 250 birth defects can be diagnosed in a fetus — many more than can be treated or cured.
What Do Prenatal Tests Find?

Among other things, routine prenatal tests can determine key things about the mother's health, including:
her blood type
whether she has gestational diabetes
her immunity to certain diseases
whether she has a sexually transmitted disease (STD) or cervical cancer

All of these conditions can affect the health of the fetus.

Prenatal tests also can determine things about the fetus' health, including whether it's one of the 2% to 3% of babies in the United States that the American College of Obstetricians and Gynecologists (ACOG) says have major congenital birth defects.

Categories of defects screened by prenatal tests include:
Dominant Gene Disorders
Recessive Gene Disorders
X-Linked Disorders
Chromosomal Disorders
Multifactorial Disorders
Dominant Gene Disorders

In dominant gene disorders, there's a 50–50 chance a child will inherit the gene from the affected parent and have the disorder. Dominant gene disorders include:
Achondroplasia, a rare abnormality of the skeleton that causes a form of dwarfism
Huntingdon disease, a disease of the nervous system that causes a combination of mental deterioration and a movement disorder affecting people in their 30s and 40s
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Recessive Gene Disorders

Because there are so many genes in each cell, everyone carries some abnormal genes, but most people don't have a defect because the normal gene overrules the abnormal recessive one. But if a fetus has a pair of abnormal recessive genes (one from each parent), the child will have the disorder. It's more likely for this to happen in children born to certain ethnic groups. Recessive gene disorders include:
Cystic fibrosis, a disease most common among people of northern European descent that is life threatening and causes severe lung damage and nutritional deficiencies
Sickle cell disease, a disease most common among people of African descent in which red blood cells form a "sickle" shape (rather than the typical donut shape), which can get caught in blood vessels and cause damage to organs and tissues
Tay-Sachs disease, a disorder most common among people of European (Ashkenazi) Jewish descent that causes mental retardation, blindness, seizures, and death
Beta thalassemia, a disorder most common among people of Mediterranean descent that causes anemia
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X-Linked Disorders

These disorders are determined by genes on the X chromosome. The X and Y chromosomes are the chromosomes that determine sex. These disorders are much more common in boys because the pair of sex chromosomes in males contains only one X chromosome (the other is a Y chromosome). If the disease gene is present on the one X chromosome, the X-linked disease shows up because there's no other paired gene to "overrule" the disease gene. One such X-linked disorder is hemophilia, which prevents the blood from clotting properly.
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Chromosomal Disorders

Some chromosomal disorders are inherited but most are caused by a random error in the genetics of the egg or sperm. The chance of a child having these disorders increases with the age of the mother. For example, according to ACOG, 1 in 1,667 live babies born to 20-year-olds have Down syndrome, which causes mental retardation and physical defects. That number changes to 1 in 378 for 35-year-olds and 1 in 106 for 40-year-olds.
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Multifactorial Disorders

This final category includes disorders that are caused by a mix of genetic and environmental factors. Their frequency varies from country to country, and some can be detected during pregnancy.

Multifactorial disorders include neural tube defects, which occur when the tube enclosing the spinal cord doesn't form properly. Neural tube defects, which often can be prevented by taking folic acid during the early part of pregnancy, include:
Spina bifida. Also called "open spine," this defect happens when the lower part of the neural tube doesn't close during embryo development, leaving the spinal cord and nerve bundles exposed.
Anencephaly. This defect occurs when the brain and head don't develop properly, and the top half of the brain is completely absent.

Other multifactorial disorders include:
congenital heart defects
obesity
diabetes
cancer
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Who Has Prenatal Tests?

Certain prenatal tests are considered routine — that is, almost all pregnant women receiving prenatal care get them. Other nonroutine tests are recommended only for certain women, especially those with high-risk pregnancies. These include women who:
are age 35 or older
have had a premature baby
have had a baby with a birth defect — especially heart or genetic problems
have high blood pressure, diabetes, lupus, asthma, or a seizure disorder
have an ethnic background in which genetic disorders are common (or a partner who does)
have a family history of mental retardation (or a partner who does)

Although your health care provider (which may be your OB-GYN, family doctor, or a certified nurse-midwife) may recommend these tests, it's ultimately up to you to decide whether to have them.

Also, if you or your partner have a family history of genetic problems, you may want to consult with a genetic counselor to help you construct a family tree going back as far as three generations.

To decide which tests are right for you, it's important to carefully discuss with your health care provider:
what these tests are supposed to measure
how reliable they are
the potential risks
your options and plans if the results indicate a disorder or defect
Prenatal Tests During the First Visit

During your first visit to your health care provider for prenatal care, you can expect to have a full physical, including a pelvic and rectal examination, and you'll undergo certain tests regardless of your age or genetic background.

Blood tests check for:
Your blood type and Rh factor. If your blood is Rh negative and your partner's is Rh positive, you may develop antibodies that prove dangerous to your fetus. This can be treated through a course of injections.
Anemia (a low red blood cell count) to make sure you're not iron deficient
Hepatitis B, syphilis, and HIV/AIDS
Immunity to German measles (rubella) and chickenpox (varicella)
Cystic fibrosis. Health care providers now routinely check for this even when there's no family history of the disorder.

Cervical tests (also called Pap smears) check for:
STDs such as chlamydia and gonorrhea
cervical cancer

To do a Pap smear, your health care provider uses what looks like a very long mascara wand or cotton swab to gently scrape the inside of your cervix (the opening to the uterus that's located at the very top of the vagina). This doesn't hurt at all; some women say they feel a little twinge, but it only lasts a second.
Prenatal Tests Performed Throughout or Later in Pregnancy

After the initial visit, your health care provider will order other tests based on, among other things, your personal medical history and needs. These tests may include:
Urine tests for sugar, protein, and signs of infection. The sugar in urine indicates gestational diabetes — diabetes that occurs during pregnancy; the protein can indicate preeclampsia — a condition that develops in late pregnancy and is characterized by a sudden rise in blood pressure and excessive weight gain, with fluid retention and protein in the urine.
Group B streptococcus (GBS) infection. GBS bacteria are found naturally in the vaginas of many women and can cause serious infections in newborns. This test involves swabbing the vagina, usually between the 35th and 37th weeks of pregnancy.
Sickle cell trait tests for women of African or Mediterranean descent, who are at higher risk for having sickle cell anemia — a chronic blood disease — or carrying the trait, which can be passed on to their children.
Other Tests

Other tests that might be performed during pregnancy include:
Ultrasound
Glucose Screening
Chorionic Villus Sampling (CVS)
Maternal Blood Screening/Triple Screen/Quadruple Screen
Amniocentesis
Nonstress Test
Contraction Stress Test
Percutaneous Umbilical Blood Sampling (PUBS)
Ultrasound
Why Is This Test Performed?

In this test, sound waves are bounced off the baby's bones and tissues to construct an image showing the baby's shape and position in the uterus. Ultrasounds were once used only in high-risk pregnancies but have become so common that they're often part of routine prenatal care.

Also called a sonogram, sonograph, echogram, or ultrasonogram, an ultrasound is used:
to determine whether the fetus is growing at a normal rate
to verify the expected date of delivery
to record fetal heartbeat or breathing movements
to see whether there might be more than one fetus
to identify a variety of abnormalities that might affect the remainder of the pregnancy or delivery
to make sure the amount of amniotic fluid in the uterus is adequate
to indicate the position of the placenta in late pregnancy (which may be blocking the baby's way out of the uterus)
to detect pregnancies outside the uterus
as a guide during other tests such as amniocentesis

Ultrasounds also are used to detect:
structural defects such as spina bifida and anencephaly
congenital heart defects
gastrointestinal and kidney malformations
cleft lip or palate
Should I Have This Test?

Most women have at least one ultrasound. The test is considered to be safe; however, it is wise to find out from your health care provider if it's the most appropriate test for you.
When Should I Have This Test?

An ultrasound is usually performed at 18 to 20 weeks to look at your baby's anatomy. If you want to know your baby's gender, you may be able to find out during this time — that is, if his or her genitals are in a visible position.

Ultrasounds also can be done sooner or later and sometimes more than once, depending on the health care provider. For example, some will order an ultrasound to date the pregnancy, usually during the first 2 months. And others may want to order one during late pregnancy to make sure the baby's turned the right way before delivery.

Women with high-risk pregnancies may need to have multiple ultrasounds using more sophisticated equipment. Results can be confirmed when needed using special three-dimensional (3-D) equipment that allows the technician to get a more detailed look at the baby.
How Is This Test Performed?

Women need to have a full bladder for a transabdominal ultrasound (an ultrasound of the belly) to be performed in the early months — you may be asked to drink a lot of water and not urinate. You'll lie on an examining table and your abdomen will be coated with a special ultrasound gel. A technician will pass a wand-like instrument called a transducer back and forth over your abdomen. High-frequency sound waves "echo" off your body and create a picture of the fetus inside on a computer screen.

You may want to ask to have the picture interpreted for you, even in late pregnancy — it often doesn't look like a baby to the untrained eye.

Sometimes, if the technician isn't getting a good enough image from the ultrasound, he or she will determine that a transvaginal ultrasound is necessary. This is especially common in early pregnancy. For this procedure, your bladder should be empty. Instead of a transducer being moved over your abdomen, a slender probe called an endovaginal transducer is placed inside your vagina. This technique often provides improved images of the uterus and ovaries.

Some health care providers may have the equipment and trained personnel necessary to provide in-office ultrasounds, whereas others may have you go to a local hospital or radiology center. Depending on where you have the ultrasound done, you may be able to get a printed picture (or multiple pictures) of your baby and/or a disc of images you can view on your computer and even send to friends and family.
When Are the Results Available?

Immediately, but a full evaluation may take up to 1 week. A radiologist (a physician experienced in obstetric ultrasound) will analyze the images and send a signed report with his or her interpretation to your doctor.

Depending on where you have the ultrasound done, the technician may be able to tell you that day whether everything looks OK. However, most radiology centers or health care providers prefer that technicians not comment until a specialist has taken a look — especially if an abnormality is detected, but even when everything is OK.
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Glucose Screening
Why Is This Test Performed?

Glucose screening checks for gestational diabetes, a short-term form of diabetes that develops in some women during pregnancy. Gestational diabetes occurs in 1% to 3% of pregnancies and can cause health problems for the baby.
Should I Have This Test?

Most women have this test.
When Should I Have This Test?

Screening for gestational diabetes usually takes place at 12 weeks for women at higher risk of having the condition, including those who:
have previously had a baby that weighs more than 9 pounds (4.1 kilograms)
have a family history of diabetes
are obese
are older than age 30

All other pregnant women are tested for diabetes at around 24 to 28 weeks. But if you've had high sugar in two routine urine tests, your health care provider may order it earlier.
How Is the Test Performed?

This test involves drinking a sugary liquid and then having your blood drawn after an hour. If the sugar level in the blood is high, you'll have a glucose-tolerance test, which means you'll drink a glucose solution on an empty stomach and have your blood drawn once every hour for 3 hours. The American Diabetes Association suggests that in order to confirm diabetes, these tests be performed at different times.
When Are the Results Available?

The results are usually available within a day, although your health care provider probably won't call you unless the reading is high and you need to come in for another test.
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Chorionic Villus Sampling (CVS)
Why Is This Test Performed?

Chorionic villi are tiny finger-like units that make up the placenta (a disk-like structure that sticks to the inner lining of the uterus and provides nutrients from the mother to the fetus through the umbilical cord). They have the same chromosomes and genetic makeup as the fetus.

This newer alternative to an amniocentesis removes some of the chorionic villi and tests them for chromosomal abnormalities, such as Down syndrome. Its advantage over an amniocentesis is that it can be performed earlier, allowing more time for expectant parents to receive counseling and make decisions.
Should I Have This Test?

Your health care provider may recommend this test if you:
are older than age 35
have a family history of genetic disorders (or a partner who does)
have a previous child with a birth defect
have had an earlier screening test that indicates that there may be a concern

Possible risks of this test include:
between a 0.5% and 1% risk of miscarriage
prematurity
early labor
infection
spotting or bleeding (this is more common with the transcervical method — see below)
When Should I Have This Test?

At 10 to 12 weeks.
How Is This Test Performed?

This test is done in one of two ways:
Transcervical. Using ultrasound as a guide, a thin tube is passed from the vagina into the cervix. Gentle suction removes a sample of tissue from the chorionic villi. No anesthetic is used, although some women do experience a pinch and cramping.
Transabdominal. A needle is inserted through the abdominal wall — this minimizes the chances of intrauterine infection, and in a woman whose uterus is in a bent position, reduces the chance of miscarriage. After the sample is taken, the doctor will check the fetus' heart rate. You should rest for several hours afterward.
When Are the Results Available?

Less than 1 week for Down syndrome and about 2 weeks for a thorough analysis.
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Maternal Blood Screening/Triple Screen/Quadruple Screen
Why Is This Test Performed?

Doctors use this to test the mother's blood only for alpha-fetoprotein (AFP). AFP is the protein produced by the fetus, and it appears in varying amounts in the mother's blood and the amniotic fluid at different times during pregnancy. A certain level in the mother's blood is considered normal, but higher or lower levels may indicate a problem. The test typically is used to determine risk for Down syndrome.

This test has been expanded, however, to also detect two pregnancy hormones — estriol and human chorionic gonadotropin (HCG) — which is why it's now sometimes called a "triple screen" or "triple marker." The test is called a "quadruple screen" ("quad screen") or "quadruple marker" ("quad marker") when the level of an additional substance — inhibin-A — is also measured. The greater number of markers increases the accuracy of the screening and better identifies the possibility of a birth defect.

This test, which also is called a multiple-marker screening or maternal serum screening, calculates a woman's individual risk of birth defects based on the levels of the three (or more) substances plus:
her age
her weight
her race
whether she has diabetes requiring insulin treatment

It's important to note, though, that this screening test determines risk only - it doesn't diagnose a condition.
Should I Have This Test?

All women are offered this test. Remember that this is a screening, not a definitive test — it indicates whether a woman is likely to be carrying an affected fetus. It's also not foolproof — spina bifida may go undetected, and some women with high levels have been found to be carrying a healthy baby. Further testing is recommended to confirm a positive result.
When Should I Have This Test?

At 16 to 18 weeks.
How Is the Test Performed?

Blood is drawn from the mother.
When Are the Results Available?

3 to 5 days, although it may take up 2 weeks.
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Amniocentesis
Why Is This Test Performed?

This test is most often used to detect:
Down syndrome and other chromosome abnormalities
structural defects such as spina bifida and anencephaly
inherited metabolic disorders

Late in the pregnancy, this test can reveal if a baby's lungs are strong enough to allow the baby to breathe normally after birth. This can help the health care provider make decisions about inducing labor or trying to prevent labor, depending on the situation. For instance, if a mother's water breaks early, the health care provider may want to try to hold off on delivering the baby as long as possible to allow for the baby's lungs to mature.

Other common birth defects, such as heart disorders and cleft lip and palate, can't be determined using this test.
Should I Have This Test?

Your health care provider may recommend this test if you:
are older than age 35
have a family history of genetic disorders (or a partner who does)
have a previous child with a birth defect

This test can be very accurate — close to 100% — but only certain disorders can be detected. According to the Centers for Disease Control and Prevention (CDC), the rate of miscarriage with this procedure is between 1 in 400 and 1 in 200. The procedure also carries a low risk of uterine infection (less than 1 in 1,000), which can cause miscarriage.
When Should I Have This Test?

At 16 to 18 weeks.
How Is the Test Performed?

A needle is inserted through the abdominal wall into the uterus to remove some (about 1 ounce) of the amniotic fluid. A local anesthetic may be used. Some women report that they experience cramping when the needle enters the uterus or pressure while the doctor retrieves the sample.

The doctor will check the fetus' heartbeat after the procedure to make sure it's normal. Most doctors recommend rest for several hours after the procedure.

The cells in the withdrawn fluid are grown in a special culture and then analyzed (the specific tests conducted on the fluid depend on personal and family medical history).
When Are the Results Available?

Timing varies; it can take up to 1 month, with the possibility that the lab will ask for a repeat. Tests of lung maturity are available immediately.
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Nonstress Test
Why Is This Test Performed?

A nonstress test (NST) can determine if the baby is responding normally to a stimulus. Used mostly in high-risk pregnancies or when a health care provider is uncertain of fetal movement, an NST can be performed at any point in the pregnancy after the 26th to 28th week when fetal heart rate can appropriately respond by accelerating and decelerating.

If you've gone beyond your due date, this test also uses external fetal monitoring to determine fetal movement. The NST can help a doctor make sure that the baby is receiving enough oxygen and that the nervous system is responding. However, a nonresponsive baby doesn't necessarily mean that the baby is in danger.
Should I Have This Test?

Your health care provider may recommend this if you have a high-risk pregnancy or if you have a low-risk pregnancy but are past your due date.
When Should I Have This Test?

At 1 week after the due date.
How Is the Test Performed?

The health care provider will measure the response of the fetus' heart rate to each movement the fetus makes as reported by the mother or observed by the doctor on an ultrasound screen. If the fetus doesn't move during the test, he or she may be asleep and the health care provider may use a buzzer to wake the baby.
When Are the Results Available?

Immediately.
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Contraction Stress Test
Why Is This Test Performed?

This test stimulates the uterus with pitocin, a synthetic form of oxytocin (a hormone secreted during childbirth), to determine the effect of contractions on fetal heart rate. It's usually recommended when a nonstress test indicates a problem and can determine whether the baby's heart rate remains stable during contractions.
Should I Have This Test?

This test is usually ordered if the nonstress test indicates a problem. It does have a high false-positive rate, though, and can induce labor.
When Should I Have This Test?

Your doctor will schedule it if he or she is concerned about how the baby will respond to contractions or feels that it is the appropriate test to determine the fetal heart rate response to a stimulus.
How Is the Test Performed?

Mild contractions are brought on either by injections of pitocin or by squeezing the mother's nipples (which causes oxytocin to be secreted). The fetus' heart rate is then monitored.
When Are the Results Available?

Immediately.
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Percutaneous Umbilical Blood Sampling (PUBS)
Why Is This Test Performed?

This test obtains fetal blood by guiding a needle into the umbilical vein. It's primarily used in addition to an ultrasound and amniocentesis if your health care provider needs to quickly check your baby's chromosomes for defects or disorders or if he or she is concerned that your baby may be anemic.

The advantage to this test is its speed. There are situations (such as when a fetus shows signs of distress) in which it's helpful to know whether the fetus has a fatal chromosomal defect. If the fetus is suspected to be anemic or to have a platelet disorder, this test is the only way to confirm this because it provides a blood sample rather than amniotic fluid. It also allows transfusion of blood or needed fluids into the baby while the needle is in place.
Should I Have This Test?

This test is used:
after an abnormality has been noted on an ultrasound
when amniocentesis results aren't conclusive
if the fetus may have Rh disease
if you've been exposed to an infectious disease that could potentially affect fetal development
When Should I Have This Test?

Between 18 and 36 weeks.
How Is the Test Performed?

A fine needle is passed through your abdomen and uterus into the fetal vein in the umbilical cord and blood is withdrawn for testing.
When Are the Results Available?

In 3 days.
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Talking to Your Health Care Provider

Some prenatal tests can be stressful, and because many aren't definitive, even a negative result may not ease any anxiety you may be experiencing. Because many women who have abnormal tests end up having healthy babies and because many of the problems that are detected can't be treated, some women decide not to have some of the tests.

One important thing to consider is what you'll do in the event that a birth defect is discovered. Your health care provider or a genetic counselor can help you establish priorities, give you the facts, and discuss your options.

It's also important to remember that tests are offered to women — they are not mandatory. You should feel free to ask your health care provider why he or she is ordering a certain test, what the risks and benefits are, and, most important, what the results will — and won't — tell you.

If you think that your health care provider isn't answering your questions adequately, you should say so. You don't have to accept the answer, "I do this test on all of my patients." Things you might want to ask include:
How accurate is this test?
What are you looking to get from these test results?/What do you hope to learn?
How long before I get the results?
Is the procedure painful?
Is the procedure dangerous to me or the fetus?
Do the potential benefits outweigh the risks?
What could happen if I don't undergo this test?
How much will the test cost?
Will the test be covered by insurance?
What do I need to do to prepare?

You also can ask your health care provider for literature about each type of test.
Preventing Birth Defects

The best thing that mothers-to-be can do to avoid birth defects is to take care of their bodies during pregnancy by:
not smoking (and avoiding second-hand smoke)
avoiding alcohol
eating a healthy diet
taking prenatal vitamins
getting exercise
getting plenty of rest
getting prenatal care

Reviewed by: Barbara P. Homeier, MD
Date reviewed: July 2005
Originally reviewed by: George A. Macones, MD

Charcot-Marie-Tooth disease Information

Charcot-Marie-Tooth disease is a progressive hereditary disorder that causes nerve damage (neuropathy). The damage in Charcot-Marie-Tooth disease occurs to your peripheral nerves or to the insulation covering your nerves (myelin sheath). The peripheral nerves are those outside of your central nervous system (brain and spinal cord). Charcot-Marie-Tooth disease most often affects the legs, arms, hands and feet. It generally results in muscle weakness and loss of muscle bulk. In some cases, it may cause a mild loss of sensation.

Named after the three physicians who first identified the disorder in 1886, Charcot-Marie-Tooth disease is a common neurological disorder. It affects about one in 3,300 people worldwide and occurs in all races and ethnic groups. Charcot-Marie-Tooth disease most often is discovered between midchildhood and age 30, but can develop at any age.

Each form of Charcot-Marie-Tooth disease has a different inheritance pattern, age of onset, signs and symptoms, severity, and progression. Other names for Charcot-Marie-Tooth disease include hereditary motor and sensory neuropathy and peroneal muscular atrophy.

Charcot-Marie-Tooth disease isn't life-threatening, and most people with the disorder lead active, productive lives. Treatments such as physical and occupational therapy often are effective in managing the signs and symptoms of Charcot-Marie-Tooth disease. Surgery may help with more severe effects of the disease.
Symptoms

The signs and symptoms of Charcot-Marie-Tooth disease (CMT) may vary from mild to severe and tend to develop slowly, sometimes appearing to stabilize spontaneously. Early signs and symptoms of CMT may include:
Weakness in your lower legs, ankles and feet
Excessively high foot arches
Flat feet
Curled toes (hammertoes)
Difficulty lifting your foot at the ankle (footdrop)
Awkward or higher than normal step (gait)
Loss of sensation in your hands or feet
Frequent tripping or falling

As CMT progresses, signs and symptoms may worsen or change. Later signs and symptoms may include:
Weakness in your arms and hands
Numbness and pain in your lower legs and feet
Decreased sensitivity to heat and cold
Causes

Charcot-Marie-Tooth disease (CMT) is an inherited genetic disease. A unique form of the disease develops depending on the particular gene mutation. Genes produce the proteins that are essential to functions of the body. In CMT, defective genes affect the proteins involved in the structure and function of your peripheral nerves or the myelin sheath. Deterioration of your peripheral nerves or the myelin sheath can send only weak signals to the muscles in your legs, arms, hands and feet, causing weakness and numbness.

CMT can be inherited in various ways:
X-linked. In X-linked inheritance, the genetic defect (mutation) is located on the X chromosome. X-linked diseases are passed from mother to son through one of the mother's genes in a pattern called X-linked recessive inheritance. A boy inherits an X chromosome from his mother and a Y chromosome from his father. The X-Y combination makes him male. A girl inherits two X chromosomes, one from her mother and one from her father. The X-X combination makes her female. Women who have a defective gene that causes a disorder are simply carriers and exhibit no signs or symptoms of the disease. The disease can skip a generation until another son inherits the defective gene on the X chromosome.
Autosomal dominant. When the genetic defect occurs on a chromosome other than X or Y, CMT affects males and females the same. Autosomal dominant inheritance of CMT results when one copy of the defective gene is enough to cause the disease. If either parent carries the defective gene for CMT, there's a 50 percent chance the disorder will be passed along to a child.
Autosomal recessive. Autosomal recessive inheritance occurs when two copies of the defective gene are required to cause CMT. One copy is inherited from each parent, neither actually having CMT.

Some types of CMT can pass from generation to generation and affect males and females equally. In other cases of CMT, the disease arises from a new or spontaneous mutation in a gene rather than from an inherited defective gene, meaning there's no previous family history of the disorder.

CMT occurs in many forms. Scientists have determined a number of genes that are involved in CMT, each linked to a specific type of the disease. The most common forms of CMT include:
CMT1. The most common type, CMT1 results from defective myelin genes, those involved in the structure and function of the insulation covering your nerves (myelin sheath). Defective myelin genes can cause a breakdown of myelin (demyelination), causing the myelin sheath to deteriorate and expose the peripheral nerves.
CMT2. This form of CMT is less common and is caused by abnormalities in the peripheral nerves as opposed to the myelin sheath.
CMT3. Also known as Dejerine-Sottas disease, CMT3 is a severe form of CMT that develops during infancy and affects the myelin sheath.
CMT4. This is the most complicated form of CMT. It involves several subtypes of demyelinating nerve damage, with each subtype caused by a different gene defect.
CMTX. The defective gene that causes CMTX is located on the X chromosome. CMTX usually affects males more than females. This is because females have two X chromosomes that can usually compensate for a defective copy of the gene on one chromosome with a normal copy on the other.
Risk factors

Charcot-Marie-Tooth disease (CMT) is hereditary, meaning that it can be passed from one family generation to the next. The severity of CMT can vary greatly within families. The risk of inheriting or passing on CMT most often depends on the type of the disorder.
Tests and diagnosis

A careful review of your family's history of nerve disease can help your doctor reach a diagnosis. In addition to a medical history review and physical examination, your doctor may rely on the following tests to diagnose Charcot-Marie-Tooth disease (CMT):
Neurological examination. During a neurological examination, your doctor looks for signs of muscle weakness in your arms, legs, hands and feet, decreased muscle bulk, reduced reflexes, and sensory loss. He or she also will look for evidence of foot deformities, such as high arches and flat feet.
Nerve conduction studies. These tests measure the strength and speed of electrical signals transmitted through your nerves. Electrodes are placed on your skin over a peripheral or sensory nerve. The electrodes produce small electric shocks that stimulate the nerve. Delayed or weak responses may indicate a nerve disorder such as CMT. Applying a topical anesthetic may ease discomfort caused by the shocks.
Electromyography (EMG). A thin-needle electrode is inserted through your skin into the muscle to be tested. Electrical activity is measured as you relax and as you gently tighten the muscle. Changes in the pattern of electrical activity can confirm CMT. Your doctor may be able to determine the distribution of the disease by testing different muscles.
Nerve biopsy. A small piece of peripheral nerve is taken from the calf of your leg through an incision in your skin. Laboratory analysis of the nerve distinguishes CMT from other nerve diseases.
Genetic testing. These tests, which can detect the most common genetic defects known to cause CMT, are done by blood sample and can result in a definite diagnosis of some types of CMT. Genetic testing for CMT may improve diagnosis and give people with the disorder more information for family planning.
Complications

Complications of Charcot-Marie-Tooth disease (CMT) vary in severity from person to person, with foot abnormalities and difficulty walking generally being the most serious problems. Muscle weakness may increase, and injury to areas of the body with decreased sensation may occur.
Treatments and drugs

There's no cure for Charcot-Marie-Tooth disease (CMT). However, some treatments can help you manage its signs and symptoms, including:
Physical therapy. Physical therapy for CMT involves muscle strengthening and stretching to prevent muscle tightening and loss. A physical therapy program usually consists of low-impact exercises and stretching techniques guided by a trained physical therapist and approved by your doctor. Started early and followed regularly, physical therapy can play an important part in delaying nerve deterioration and muscle weakness before disability is present.
Occupational therapy. Some people with CMT may experience weakness in their arms and hands, causing difficulty with gripping and finger movement. Normal daily activities, such as fastening buttons or writing, can become difficult. Occupational therapy can help you deal with such challenges through the use of assistive devices, such as special rubber grips on doorknobs or clothing with snaps instead of buttons.
Orthopedic devices. Many people with CMT require the help of certain orthopedic devices to maintain everyday mobility and to prevent injury. Leg and ankle braces or splits can provide stability during walking and climbing stairs. Wearing boots or high-top shoes may provide additional ankle support. Custom-made shoes or shoe inserts may improve your gait. If you have hand weakness and difficulty with gripping and holding things, thumb splints may help.
Surgery. If the signs and symptoms of CMT become severe and other treatment methods don't help, surgery may be an option to reverse foot and joint deformities. Ankle surgery may stabilize the ankle or provide better distribution of weight. Foot surgery is discouraged if special footwear or supportive orthopedic devices can help instead.

Research continues to provide additional treatment options that might stop or reverse the effects of CMT. Studies are also under way to determine if CMT can be prevented. Future treatment may include the use of gene replacement therapy, which may involve delivering specific genes to certain cells and muscles, and using nerve growth factors, such as the hormone androgen, to prevent nerve deterioration caused by CMT. Other research includes treating CMT with stem cells. In recent laboratory experiments, scientists have found ways to turn stem cells into nerve cells and myelin-producing cells. It may be possible to use these cells to replace the damaged or diseased cells that cause CMT or to repair nerves damaged by the effects of the disease.
Lifestyle and home remedies

Certain tactics may prevent complications caused by Charcot-Marie-Tooth disease (CMT) and improve your ability to manage the effects of the disorder. Started early and followed regularly, at-home activities can provide protection and relief:
Practice stretching. The goal of stretching is to improve or maintain the range of motion of your joints. Stretching improves your flexibility, balance and coordination. Stretching may also reduce your risk of injury. If you have CMT, regular stretching can prevent or reduce joint deformities that may result from uneven pulling of muscle on your bones.
Exercise regularly. Daily exercise keeps your bones and muscles strong. Low-impact exercises, such as biking and swimming, are less stressful on fragile muscles and joints. By strengthening your muscles and bones, you can improve your balance and coordination, reducing your risk of falls.
Improve stability. Muscle weakness associated with CMT may cause you to be unsteady on your feet, which can lead to falling and serious injury. Walk with a cane to increase your stability. Good lighting at night can help you avoid stumbling and falling.
Coping and support

Support groups can be valuable in dealing with Charcot-Marie-Tooth disease (CMT). They bring together people who are coping with the same kind of physical or mental health challenge, along with their family and friends. Support groups provide a setting in which people can share their common problems and provide ongoing support to one another.

Ask your doctor about support groups in your community. Your local health department, public library, telephone book and the Internet also may be good sources to find a support group in your area.

By Mayo Clinic Staff