PPP2R5D and early-infantile DEE: Previously observed pathogenic de novo missense variants were detected in PPP2R5D associated with autosomal dominant intellectual disability (MRD35, OMIM #616,355); ACTB which causes Baraitser-Winter syndrome (BRWS1, OMIM #243,310); CYFIP2 which underlies a mild form of early infantile epileptic encephalopathy (EIEE65, OMIM #618,008); and DYNC1H1 associated with intellectual disability (MRD13, OMIM #614,563) (Figure S1A; Tables 1, 2 & Table S1).