Mondo Description Kleefstra syndrome (KS) is 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.
Disease Ontology Description A syndrome characterized by childhood hypotonia, a distinctive facial appearance, speech impediments and developmental disability, as well as epilepsy, congenital and urogenetic defects, microcephaly, corpulence, and psychiatric disorders. It is caused either by a microdeletion in the chromosome region 9q34.3 or by a point mutation in the EHMT1 gene located in that region.