[Tuberous Sclerosis Complex]

Tuberous sclerosis complex (TSC) is an autosomal dominant inherited disorders that is characterized by the systemic hamartomas, along with epilepsy, cognitive impairment and hypopigmented macules. It is caused by genetic mutations in either TSC1 or TSC2 gene which encodes hamartin and tuberin, respectively. As the hamartin-tuberin-complex downregulates the mechanistic/mammalian target of the rapamycin complex1 (mTORC1), dysfunction in either hamartin or tuberin induces the constitutive activation of mTORC1. In fact, almost all the symptoms in TSC are derived from the activation of mTORC1. Therefore, mTORC1 inhibitors improves all the symptoms, including skin lesions and neural symptoms. Among the many symptoms, skin lesions appear earlier than renal or pulmonary lesions and are more specific than neuronal symptoms. Therefore, skin lesions are useful for the diagnosis of TSC. This chapter focuses on the features of skin lesions and mechanistic their potential role in differential diagnosis and therapy including the therapeutic use of mTORC1 inhibitors.