TSC1 and tuberous sclerosis: TSC is caused by loss-of-function mutations in TSC1 or TSC2 genes, which act as tumor growth suppressors and encode the proteins hamartin and tuberin and have been found to be responsible for the mTOR pathway (van Slegtenhorst et al., 1997; European Chromosome 16 Tuberous Sclerosis Consortium, 1993).