MECP2 and autism spectrum disorder: Loss of constraints on protein synthesis due to mutations in negative regulators of translation (FMR1, MECP2, or mTORC1 suppressors including NF1, TSC1/2, or the phosphatase PTEN) are associated with cognitive impairment and high incidence of autism spectrum disorders and intellectual disability (Kelleher and Bear, 2008), although a fraction of autistic individuals exhibit enhanced cognitive skills within specific domains (Heaton and Wallace, 2004).