 The syndrome is also often referred to by the broader term Chromosome 15q11.2-q13.1 Duplication Syndrome, shortened to Dup15q syndrome.Dup15q syndrome is a broader disease term, as it includes both idic(15) and interstitial 15q11.2-q13.1, another type of duplication that causes similar clinical traits.The extra chromosome is occasionally found in the mosaic state, i.e.