Identification of mutations in TSC1 or TSC2 that prevent the production or function of their protein products (estimated by nonsense mutations, truncations, etc. or that are verified as non-functional) is sufficient for the diagnosis of TSC (Northrup et al., 1999; Hoogeveen-Westerveld et al., 2012, 2013). This evidence concerns the gene TSC1 and tuberous sclerosis.