The monogenic forms of ASD include FXS (loss of FMRP), Tuberous Sclerosis Complex (mutation of either TSC1 or TSC2), Angelman Syndrome (loss of Ube3a-dependent ubiquitination), and Phelan-McDermid syndrome (disruption of the Shank3 scaffold protein). Here, FMR1 is linked to fragile X syndrome.