Distal monosomy 12p is a rare partial autosomal monosomy characterized by language development delay with childhood apraxia of speech, mild intellectual disability, behavourial abnormalities (autistic spectrum disorder, attention deficit hyperactivity disorder, anxiety) and mildly dysmorphic nonspecific features. Additional clinical features may include muscular hypotonia and joint laxity, hernias and microcephaly. The disease is Monarch Disease Ontology term MONDO_0017229 (distal monosomy 12p). Also known as: 12p13.33 microdeletion syndrome, Del(12)(p13.33), distal deletion 12p, distal monosomy type 12p.