A genetic disorder characterized by intellectual disability, childhood hypotonia, severe expressive speech delay and a distinctive facial appearance with a spectrum of additional clinical features. The disease is MONDO_0012455 (Kleefstra syndrome). Also known as: 9Q subtelomeric deletion syndrome, 9Q- syndrome, 9q-syndrome, 9q34 deletion syndrome, 9q34.3 microdeletion syndrome, chromosome 9Q34.3 deletion syndrome, chromosome 9q deletion syndrome.