distal trisomy 20q (MONDO_0019888) is a rare chromosomal anomaly syndrome, resulting from the partial trisomy of the long arm of chromosome 20, with high phenotypic variability mostly characterized by neurodevelopmental delay, cardiac malformations (e.g. ventricular septal defect, coarctation of aorta) and facial dysmorphism (incl. large/high forehead, microphthalmia, upslanting palpebral fissures, epicanthus, large, long, low-set ears, anteverted nares, protruding upper lip, cleft lip/palate, micro/retrognathia, dimpled chin). Skeletal (brachydactyly, scoliosis, pectus excavatum) and cerebral anomalies have also been reported. Also known as: distal duplication 20q, distal trisomy type 20q, telomeric duplication 20q, trisomy 20qter.