Duplication of 20qter and deletion of 20pter due to paternal pericentric inversion: Patient report and review of 20qter duplications

Duplications of the terminal long arm of chromosome 20 are rare chromosomal anomalies. We report a male infant found on array comparative genomic hybridization analysis to have a 19.5Mb duplication of chromosome 20q13.12-13.33, as well as an 886kb deletion of 20p13 at 18,580-904,299bp. This anomaly occurred as the recombinant product of a paternal pericentric inversion. There have been 23 reported clinical cases involving 20qter duplications; however, to our knowledge this is only the second reported patient with a paternal pericentric inversion resulting in 46,XY,rec(20)dup(20q). This patient shares many characteristics with previously described patients with 20qter duplications, including microphthalmia, anteverted nares, long ears, cleft palate, small chin, dimpled chin, cardiac malformations, and normal intrauterine growth. While there is variable morbidity in patients with terminal duplications of 20q, a review of previously reported patients and comparison to our patient's findings shows significant phenotypic similarity.