STXBP1 and autism: A 21% decrease in the abundance of Munc18-1 in the brain has previously been found in Nlgn1 KO mice that display impaired spatial memory and increased repetitive behavior.31 Interestingly, a genome-wide copy number variation analysis has implicated NLGN1 as a candidate gene in autism susceptibility.46 A significant decrease in expression of Munc18-1 could conceptually be important for both excitatory and inhibitory transmission.