Heart and Brain Malformation Syndrome, also known as neurodevelopmental disorder with heart and brain malformations, is related to syndromic intellectual disability and microcephaly. An important gene associated with Heart and Brain Malformation Syndrome is SMG9 (SMG9 Nonsense Mediated MRNA Decay Factor). Affiliated tissues include brain and heart, and related phenotypes are ventricular septal defect and hand clenching