MTOR and tuberous sclerosis: Treatment development in ASD is also challenged by the phenotypic and etiologic heterogeneity of the disorder [Geschwind & Levitt, 2007], including the evidence that the core symptom dimensions may have separate genetic architectures [Ronald et al., 2006], which hinders the identification of drug targets, compared with other single gene disorders (e.g., mammalian Target Of Rapamycin (mTOR) pathway in tuberous sclerosis).