Tuberous Sclerosis (TSC) Support Group

General Discussion
Tuberous sclerosis is a rare genetic multisystem disorder that is typically apparent shortly after birth. The disorder may be characterized by episodes of uncontrolled electrical activity in the brain (seizures); mental retardation; distinctive skin abnormalities (lesions); and benign (noncancerous), tumor-like nodules (hamartomas) of the brain, certain regions of the eyes (e.g., retinas), the heart, the kidneys, the lungs, or other tissues or organs. In addition, many affected individuals may have cyst-like areas within certain skeletal regions, particularly bones of the fingers and toes (phalanges). Characteristic skin lesions include sharply defined areas of decreased skin coloration (hypopigmentation) that may develop during infancy and relatively small reddish nodules that may appear on the cheeks and nose beginning at approximately age four. These reddish lesions eventually enlarge, blend together (coalesce), and develop a wart-like appearance (sebaceous adenomas). Additional skin lesions may also develop, including flat, "coffee-colored" areas of increased skin pigmentation (café-au-lait spots); benign, fibrous nodules (fibromas) arising around or beneath the nails; or rough, elevated, "knobby" lesions (shagreen patches) on the lower back.

Tuberous sclerosis results from changes (mutations) in a gene or genes that may occur spontaneously (sporadically) for unknown reasons or be inherited as an autosomal dominant trait. Most cases represent new (sporadic) gene mutations, with no family history of the disease. Mutations of at least two different genes are known to cause tuberous sclerosis. One gene (TSC1) has been mapped to the long arm (q) of chromosome 9 (9q34). A second gene for the disease (TSC2) is located on the short arm (p) of chromosome 16 (16p13.3). It remains unclear whether some sporadic and familial cases of the disease may be caused by mutations of other, currently unidentified genes (genetic heterogeneity).
Posted on 09/28/07, 05:09 pm