De Novo Pure Trisomy 20p: Report of a Novel Case of a Marker Chromosome and Literature Review

Dear Editor, Trisomy 20p is a rare genetic disorder manifesting as intellectual disability, speech delay, specific facial features, and delayed motor milestones. Severity of the symptom depends on chromosome 20p duplication size; larger chromosomal duplications usually result in more serious symptoms [1]. Most previously reported cases involved partial trisomy 20p derived from a parental reciprocal translocation, chromosome inversion, or a small supernumerary marker chromosome (sSMC) [1-5]. However, only a few cases of pure trisomy 20p (involving whole short arm of chromosome 20) have been reported [1, 5-9]. KCI Citation Count: 1