Fabry disease Overview:
Fabry disease is an inherited disorder that results from the buildup of a particular type of fat in the body's cells. Beginning in childhood, this buildup causes signs and symptoms that affect many parts of the body. Characteristic features of Fabry disease include episodes of pain, particularly in the hands and feet (acroparesthesias); clusters of small, dark red spots on the skin called angiokeratomas; a decreased ability to sweat (hypohidrosis); cloudiness of the front part of the eye (corneal opacity); and hearing loss. Fabry disease also involves potentially life-threatening complications such as progressive kidney damage, heart attack, and stroke. Milder forms of the disorder may appear later in life and affect only the heart or kidneys.
Fabry disease is caused by the lack of or faulty enzyme needed to metabolize lipids, fat-like substances that include oils, waxes, and fatty acids. The enzyme is known as ceramide trihexosidase, also called alpha-galactosidase-A. A mutation in the gene that controls this enzyme causes insufficient breakdown of lipids, which build up to harmful levels in the eyes, kidneys, autonomic nervous system, and cardiovascular system. Since the gene that is altered is carried on a mother’s X chromosome, her sons have a 50 percent chance of inheriting the disorder and her daughters have a 50 percent chance of being a carrier. Some women who carry the genetic mutation may have symptoms of the disease. Symptoms usually begin during childhood or adolescence and include burning sensations in the hands that gets worse with exercise and hot weather and small, raised reddish-purple blemishes on the skin. Some boys will also have eye manifestations, especially cloudiness of the cornea. Lipid storage may lead to impaired arterial circulation and increased risk of heart attack or stroke. The heart may also become enlarged and the kidneys may become progressively involved. Other symptoms include decreased sweating, fever, and gastrointestinal difficulties, particularly after eating. Fabry disease is one of several lipid storage disorders.
Fabry's disease is a fat storage disorder caused by a deficiency of an enzyme involved in the biodegradation of lipids.
The gene for this disorder is on the X-chromosome, so only the mother needs to be a carrier to produce an affected child. Her sons have a 50 percent chance of having the condition, and her daughters have a 50 percent change of being a carrier.
Some of the female carriers exhibit signs of the condition, especially cloudiness of the cornea. In addition to the eye manifestations, males characteristically have burning sensations in their hands and feet that is worse with exercise and hot weather. Most of the males have small, raised, reddish-purple blemishes on their skin.
As they grow older, they may have impaired arterial circulation leading to early heart attacks and strokes. The kidneys become progressively involved, and many patients require kidney transplantation or dialysis.
A number of patients have gastrointestinal difficulties characterized by frequent bowel movements shortly after eating. This disorder is due to a deficiency of a lipid breakdown enzyme known as ceramidetrihexosidase, also called alpha-galactosidase A. Its function is to cleave to a molecule of galactose from a lipid that arises primarily from old red blood cells.
The pain in the hands and feet usually responds to medications such as Tegretol (carbamazepine) and dilantin. Gastrointestinal hyperactivity may be treated with metoclopramide or Lipisorb® (a nutritional supplement). Early experiments have indicated that enzyme replacement may be useful.
Patients with Fabry's disease usually survive into adulthood, but they are at risk for strokes, heart attacks, and kidney damage. |
