ABSTRACT
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by a mutation of either the chromosome 9 TSC1 gene or the chromosome 16 TSC2 gene. With a prevalence of about one per 6000, TSC is one of the more common of the neurocutaneous diseases. By comparison, the most common neurocutaneous disorder, neurofibromatosis type 1, has a prevalence of about one per 4000. An inherited or sporadic mutation of either TSC1 or TSC2 results in loss of function or aberrant function of the respective gene product: hamartin (chromosome 9 TSC1) or tuberin (chromosome 16 TSC2). These two genes are thought to act in part as tumor suppressor genes, but also function in various aspects of the regulation of cell growth, migration, and development. In the 1=3 of TSC patients whose families demonstrate autosomal dominant inheritance, the mutation occurs roughly equally in either TSC1 or TSC2. By contrast, TSC2 is more often mutated in the two-thirds of patients who have TSC due to a spontaneous mutation. TSC typically causes problems that affect one or more of four organs: brain, skin, kidneys, and lungs.
