Distal duplication of chromosome 16q22.1q23.1 in a Vietnamese patient with midface hypoplasia and intellectual disability.

The clinical presentation of distal duplications of the long arm of chromosome (chr) 16 is currently not well described. Only one case of microduplication of chr16q22.1 and another involving the chr16q22.1q23.1 region have been reported so far. Here, using array comparative genomic hybridization, we identified a second case of chr16q22.1q23.1 duplication in a Vietnamese boy, who shares significant clinical phenotype with the previously described case. Aside from developmental delay, intellectual disability and midface hypoplasia, our patient also displays a forked tongue, visual impairment and external ptosis. Our report further expands the clinical spectrum associated with duplication of this region.