MONDO_0015740 (trisomy 18p) is an extremely rare chromosomal anomaly with a poorly defined clinical phenotype. Reported manifestations include short stature, mild, moderate or severe developmental delay and intellectual disability, variable but mild facial dysmorphism, and epilepsy. Also known as: Duplication 18p, Duplication of the short arm of chromosome 18, trisomy of the short arm of chromosome 18, trisomy type 18p.