SHANK3 and autism: Mechanistically, several actin regulators including Abp1, cortactin, cofilin, and Rac1, have altered expression or activity associated with Shank3 deficiency or autism-related mutations that contribute to dendritic spine reduction and synaptic dystrophy (Haeckel et al., 2008; Durand et al., 2012; Duffney et al., 2015).