PPP2R5D and neurodevelopmental disorder: Following the first report of PPP2R5D-related neurodevelopmental disorder in patients who were described with mild to severe ID, hypotonia, susceptibility to epilepsy, facial dysmorphisms including frontal bossing, hypertelorism, and downslanting palpebral fissures, the number of reported cases has increased exponentially, thanks to the wide application of exome sequencing.