A novel nonsense mutation in PPP2R5D is associated with neurodevelopmental disorders and shows incomplete penetrance in a Chinese pedigree

PPP2R5D mutations are known to cause neurodevelopmental disorders in an autosomal-dominant manner. To date, the vast majority of the reported cases in the literature have been sporadic with de novo mutations. There are no data regarding PPP2R5D mutation penetrance. We aimed to unravel the underlying genetic defects in 3 generations of a family affected by intellectual disability, neurodevelopmental delay, and facial dysmorphology. We performed detailed clinical examinations and whole-exome sequencing in the family. We identified a novel mutation, c.1321 C>T (p.Arg441*), in PPP2R5D. The mutation cosegregated with affected family members I-2 and II-7 but not II-3, who bears the mutation but is phenotypically healthy. Our whole-exome sequencing also excluded the involvement of pathogenic mutations in other genes known to be related to neurodevelopmental disorders. The mutation was predicted to introduce a premature stop codon at position 441, thereby truncating the 162 amino acids at the C-terminus of the encoded protein. We report a familial transmitted PPP2R5D-related neurodevelopmental disorder as well as a novel nonsense pathogenic mutation and its incomplete penetrance. Our study expands the mutational and phenotypic spectra of PPP2R5D-related neurodevelopmental disorders, broadens our understanding of these disorders, and will thus be valuable for mutation-based pre- and postnatal screening and genetic diagnosis of neurodevelopmental disorders.