Duplication of 9p

Figure 1: Chromosome 9

An extra copy of the short arm of chromosome 9 is called a duplication of 9p. Patients with duplication of 9p has Trisomy 9p syndrome.

More than 150 patients with Trisomy 9p have been found since 1970. Major clinical features observed include small stature, mental retardation, microcephaly/brachycephaly and dysmorphic features with deep set eyes, down-turned mouth, low-set ears, down-slanting palpebral fissures, prominent nose, single palmar crease, hypoplasia of some phalanges, and hypoplastic nails. In addition, cleft lip or palate, small lower jaw, talipes and congenital hip dislocation have been described. Duplication of 9p can be a de novo abnormality or part of a more complex chromosomal rearrangement, e.g. inherited from a balanced reciprocal translocation carrier.