What is (are) 15q13.3 microduplication syndrome ?
15q13.3 microduplication syndrome is a rare chromosome abnormality first described in 2009. Since only a small number of individuals with this microduplication have been reported, the full range of effects is still being discovered. What is known is that the symptoms are variable, even between members of the same family. While some people with this microduplication do not have symptoms, several features seem to be common, including delayed development, intellectual disability, communication difficulties, emotional and behavioral problems (including autistic spectrum disorders), insomnia, and seizures. 15q13.3 microduplication syndrome is caused by a tiny duplication (microduplication) on the long arm of chromosome 15 that spans at least 6 genes. The features of this syndrome are thought to be caused by the presence of three copies of the genes in this region, instead of the normal two. However, it is unclear which genes contribute to the specific features. In addition, it is likely that other genetic or environmental factors influence the symptoms seen in this condition. Some cases of 15q13.3 microduplication syndrome are inherited in an autosomal dominant manner with reduced penetrance. Other cases are new (de novo). Treatment typically focuses on treating the symptoms (such as medication for seizures).