SHANK genes, including SHANK1, SHANK2 and SHANK3, directly encode the proteins in the postsynaptic scaffolding protein family, which are located in the PSDs of excitatory synapses.177 SHANKs were first implicated in ASD by studies on Phelan–McDermid syndrome,200,201 a neurodevelopmental disorder caused by 22q13.3 deletion, and are deleted in almost all reported Phelan–McDermid syndrome cases. Here, SHANK2 is linked to neurodevelopmental disorder.