Monarch Disease Ontology identifier MONDO_0007838 (Jacobsen syndrome) is a multiple congenital anomaly/intellectual disability contiguous gene syndrome caused by partial deletion of the long arm of chromosome 11. Also known as: 11q terminal deletion disorder, Del(11)(q23.3), Del(11)(qter), Jacobsen syndrome, Isolated cases, distal deletion 11q, distal monosomy 11q, monosomy 11qter, telomeric deletion 11q.