Diagnosis of Tuberous Sclerosis Complex

E. Steve Roach MD; Steven P. Sparagana MD


J Child Neurol. 2004;19(9):643-649. 

In This Article

Genetics of Tuberous Sclerosis

Tuberous sclerosis complex was once thought to be a rare disease but is now known to occur in about 1 in 6000 live births,[18] making it not quite as common as neurofibromatosis type 1 (1 in 4,000 births) but more common than von Hippel-Lindau disease (1 in 36,000 births). Improved diagnostic techniques (especially in imaging and genetic testing), as well as an ever-growing awareness of tuberous sclerosis complex among physicians and the public, might, in time, reveal an even greater prevalence.

Tuberous sclerosis complex is inherited as an autosomal dominant trait with variable penetrance, and two thirds to three fourths of the individuals with tuberous sclerosis complex arise via a spontaneous mutation. Two different genes cause tuberous sclerosis complex: TSC2, which encodes tuberin, and TSC1, which encodes hamartin.[19,20] Multiple mutations of each gene have been identified. The phenotype for the two tuberous sclerosis complex genes overlap, although individuals with TSC2 tend to have more severe neurologic impairment, and TSC1 tends to be found more often in familial cases.[11] Tuberin and hamartin physically interact at the Golgi apparatus and function together as a single molecular complex, probably explaining why a mutation on either gene causes such a similar phenotype.[22,23,24]


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