Trisomy 9p is a rare chromosomal anomaly syndrome, resulting from a partial or complete trisomy of the short arm of chromosome 9, with a wide phenotypic variablility, typically characterized by intellectual disability, craniofacial dysmorphism (e.g. microcephaly, large anterior fontanel, hypertelorism, strabismus, downslanting palpebral fissures, malformed, low-set, protruding ears, bulbous nose, macrostomia, down-turned corners of mouth, micrognathia), digital anomalies (brachydactyly and clinodactyly), and short stature. Less frequently patients present with cardiopathy and renal, skeletal, and central nervous system malformations.
Characterization of partial trisomy 9p due to insertional translocation by chromosomal (micro)FISH.
de Pater JM, Ippel PF, van Dam WM, Loneus WH, Engelen JJ. Clin Genet. 2002;62(6):482-7.
The proband manifests typical features of trisomy 9p; the clinical signs were mental and growth retardation, microcephaly, epicanthus, low-set ears, micrognathia, clinodactyly and hypoplastic phalanges of the fifth fingers, hypoplasia or absence of toenails, and extremely small genitals.
