20q11.2 microduplication syndrome is a rare chromosomal anomaly syndrome, due to partial duplication of the long arm of chromosome 20, characterized by psychomotor and developmental delay, moderate intellectual disability, metopic ridging/trigonocephaly, short hands and/or feet and distinctive facial features (epicanthus, hypoplastic supraorbital ridges, horizontal/downslanting palpebral fissures, small nose with depressed nasal bridge and anteverted nostrils, prominent cheeks, retrognathia and small, thick ears). Growth delay and cryptororchidism are often associated features. The disease is 20q11.2 microduplication syndrome (MONDO_0018204, a Monarch Disease Ontology entry). Also known as: dup(20)(q11.2).