Fabry disease is an inherited disorder. It is one of a family of hereditary diseases called lysosomal storage disorders that affect the way certain important chemicals are processed in the body. Fabry disease is rare; it is found in roughly 1 in 117,000 people.
Lysosomal storage disorders (LSDs) are a group of rare genetic conditions caused by enzyme deficiencies. In a lysosomal storage disorder, certain structures in cells, called lysosomes, have trouble breaking down specific complex fatty molecules. As a result, the lysosomes fill up with these undigested molecules, impairing the cell’s ability to function properly.
In people with Fabry disease, cells store up a fatty substance called globotriaosylceramide (GL-3), which is normally cleared out of cells by an enzyme called alpha-galactosidase A (alpha-GAL A).
With Fabry disease, the body doesn’t produce enough functional alpha-GAL A to break down the GL-3. Because it is not broken down, the GL-3 accumulates in cell lysosomes. Over time, excessive build-up of GL-3 can cause damage in tissues throughout the body.
The defective gene that causes Fabry disease is located on the X chromosome. Males have only one X chromosome, so when they carry the defective gene, they will likely not be able to make enough alpha-GAL A to prevent GL-3 build-up. Even though women have two X chromosomes, their unaffected chromosome does not always compensate for the affected chromosome. Some women who carry the defective gene will develop symptoms, while others will not.
Many of the symptoms of Fabry disease are also common to other diseases, which may make diagnosis difficult. In addition, the symptoms of Fabry disease can occur differently for every individual. Each person with Fabry may have all or only a few of the typical signs and symptoms or may experience symptoms at different times throughout life. That’s why it’s important to discuss symptoms and risk factors, as well as whether there are other family members with known or suspected Fabry disease, with a doctor.
Some of the more common symptoms of Fabry disease include:
- Pain and burning in the hands and feet
- Impaired sweating
- Low tolerance for exercise
- Dark red skin rashes (angiokeratomas)
- Eye abnormalities (such as corneal whorling) that do not typically affect vision
- Gastrointestinal problems
- Heart problems
- Kidney problems
- Nervous system problems, such as weakness, head pain, numbness, dizziness, or stroke
- Hearing problems
- Psychological and social issues
Fabry disease was once thought to affect only males; females were generally considered to be only “carriers” of the defective gene, and not vulnerable to Fabry disease symptoms. The medical community is learning that females with the defective gene are more than carriers, and do, in fact, develop a wide range of symptoms.
The earlier Fabry disease is diagnosed, the sooner health care providers can intervene and help patients manage the disease. However, because Fabry disease is uncommon and its symptoms are not well recognized or may be mistaken for those of other illnesses, diagnosis of Fabry disease is often delayed.
In males, a lack of alpha-GAL A enzyme activity shows they have inherited the defective gene. Males can usually be diagnosed through a blood test called an enzyme assay that measures the amount of alpha-GAL A in the blood.
Females, however, can have normal amount of alpha-GAL A and still carry the defective gene, since Fabry disease is linked to the X chromosome. Females with Fabry disease may have one or more severely affected organs, such as the heart or kidney, but have nearly normal alpha-GAL A in their blood. For this reason, a genetic test is needed for an accurate diagnosis.
Consult your doctor if you believe you or someone you know has exhibited symptoms of Fabry disease.