RPS6KA5 and autism spectrum disorder: This dysregulation of spine number in the MSK1 KD mutant may contribute in particular to the cognitive impairments seen in MSK1 KD mice after enrichment and has parallels with the greater spine density and impaired cognition observed in both human autism spectrum disorder and animal models of autism (Coley and Gao, 2018; Nakai et al., 2018).