PAK1 and fragile X syndrome: Most remarkably, more recent studies demonstrate that inhibition of PAK1, either genetically or pharmacologically, can ameliorate the cognitive and social deficits in several animal models of neurodevelopmental disorders, particularly autism, including genetic models targeting fragile X syndrome and neurofibromatosis (Dolan et al., 2013; Hayashi et al., 2007; Molosh et al., 2014).