Fabry Disease - Multi-Ethnic Genetic Disease

Description
Fabry disease is an inherited disease that affects anywhere from a few thousand to 50,000 people worldwide. The most common form of Fabry appears at twenty years of age. This disease is caused by a deficiency of lysosomal enzyme a-galactosidase, which causes abnormal deposits of a fatty substance called globotriaosylcera-mide in the blood vessels throughout the body.

As abnormal storage of the fatty compound increases with time, the channels of these vessels become narrowed. The narrowing leads to a decreased blood flow and decreased nourishment of the tissues normally supplied by those vessels. The problem occurs in all blood vessels throughout the body, but affect in particular the skin, the kidneys, the heart, the brain, and the nervous system. A characteristic rash around the waist develops, and there is an increased risk of kidney and heart disease as well as a reduced life expectancy.

Symptoms
In children it begins with episodes of pain and burning sensations in hands and feet.
Young patients often develop spotted dark red skin rash seen more from umbilicus to knees, decreased ability to perspire, change in cornea that does not affect vision.

Fabry is a progressive disease. Symptoms of kidney, heart, and/or neuro involvement occur between ages of 30-45.

Incidence and Carriers
(Fabry Diseases is LESS prevalent amongst Jews than in the rest of the global population. Not a "Jewish Genetic Disease.")

The defective gene is on the X-chromosome. The X-chromosome is one of two chromosomes that determine a person's sex. Females have two X-chromosomes, one from each parent. Males have X-chromosome from mom and Y-chromosome from dad.

If mother is a carrier of the Fabry Disease, all her male and female children have 50% chance of inheriting a defective gene from their mother.

If father is carrier all daughters will inherit the defective gene, since it is the one X-chromosomes that is transferred from fathers to daughters. Son, who get the Y-chromosome from their father do not inherit the defective gene.

A female Fabry carrier has one X-chromosome with a defective gene and normal one X-chromosome, thus she is usually protected. Males, on the other hand, have only one X-chromosome, so when that gene is defective, they express the disease.

Fabry Disease occurs in all ethnic groups. It is estimated that one in 200 people is a carrier, and one in 40,0000 has the disease.

Treatment
Treatment for Fabry disease is at first preventative. Certain factors such as stress, exposure to sunlight, and change in temperature, physical exertion, illness and fever trigger painful episodes. Patients need to avoid these triggers to prevent the painful episodes. Anticonvulsant medications such as Dilantin or Tegretol may be given for reduce frequency of painful attacks.

Treatment is then geared toward any complications of the kidney. Mild kidney dysfunction can be treated with diet, and those with severely compromised kidney function are treated with dialysis and maybe candidates for kidney transplant.

Testing
Once pregnant an Amniocentesis and a Chorionic Villus Sampling can diagnose Fabry in the fetus before birth. Amniocentesis is done between the 15th and 16th week of pregnancy. A needle is inserted into the mother's abdomen and a sample of the fluid that surrounds the baby is taken. In CVS a sample of cells from the placenta is retrieved by the doctor during the 10th and 12th week of a pregnancy.

When Fabry disease is suspected either on basis of clinical signs or by discovery of relative with Fabry disease it is confirmed by simple blood test that measures activity of enzyme.

Resources and More
    International Center for Fabry Disease
    Dept. of Human Genetics, Mount Sinai School of Medicine
    5th Avenue and 100th Street
    New York, NY 10029
    Telephone: 212-659-6700

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