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.

Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here.