Distal 16p11.2 microdeletion syndrome is a rare chromosomal anomaly syndrome resulting from the partial deletion of the short arm of chromosome 16 with a highly variable phenotype typically characterized by developmental delay, mild intellectual disability and autism spectrum disorder. Macrocephaly (apparent by 2 years of age), structural brain malformations, epilepsy, vertebral anomalies and obesity are frequently associated. The disease is Monarch Disease Ontology entry MONDO_0013267 (distal 16p11.2 microdeletion syndrome). Also known as: body mass index QTL16, chromosome 16p11.2 deletion syndrome, type 220kb, distal del(16)(p11.2), distal monosomy 16p11.2.