PPP2R1A and Cognitive impairment: Presently, diseases caused by PPP2R1A gene mutations are defined as PPP2R1A-related NDD [12], with clinical features including severe hypotonia, varying degrees of intellectual impairment and developmental delay, abnormal head circumference, epilepsy, attention deficit, dysplasia of the corpus callosum, etc. Currently, more than 60 patients have been reported [2,4,7,10,13,14,15].