Pathogenic variants in SETD1A have been reported in association with early onset epilepsy, neurodevelopmental delay and an increased risk of schizophrenia (MIM:618832; MIM:619056), and variants in SETD1B (MIM:619000), SETD2 and SETD5 (MIM:616761) have also been associated with NDDs (22–26). The gene discussed is SETD1B; the disease is Neurodevelopmental delay.