Trisomy 20p is a chromosomal disorder resulting from duplication of all or part of the short arm of chromosome 20. It is mostly characterized by normal growth, mild to moderate intellectual disability, speech delay, poor coordination and evocative facial features. The disease is Monarch Disease Ontology term MONDO_0016844 (trisomy 20p). Also known as: Duplication of 20p, dup(20p), partial duplication of chromosome 20p, partial duplication of the short arm of chromosome 20, partial trisomy of chromosome 20p, partial trisomy of the short arm of chromosome 20, trisomy type 20p.