Recognizing an index case of tuberous sclerosis.

Tuberous sclerosis is the most common neurocutaneous syndrome after neurofibromatosis. Dermatologic manifestations may be the only clues the family physician has to the diagnosis of the disorder, which is also marked by childhood seizures and mental retardation. Characteristic signs of tuberous sclerosis vary widely in severity and can include hypopigmented "ash-leaf spots," fibrous plaques on the forehead, angiofibromas on the face (adenoma sebaceum), a shagreen patch on the lower back and fibromas of the nails. Computed tomographic scanning or magnetic resonance imaging reveal subependymal nodules or cortical "tubers" in the brain. Associated cardiac, retinal, renal and pulmonary pathology can increase morbidity and mortality. Genetic counseling is helpful but has limited use because of the variation in genetic expression and the frequency of new gene mutations that cause this disorder.