Study Clarifies Link Between 15q Duplication and Autism

Children who carry an extra copy of the 15q11-13 region of the genome usually have autism and sleep troubles, as well as distinctive brain-wave patterns and facial features, according to a report published 14 March in Autism Research.The study is the largest to date characterizing the effects of a rare type of duplication in this region. This large chromosomal region, dubbed '15q,' is the most common site for autism-related DNA deletions and duplications.It's also famous for its complexity: Losing 15q on the maternal chromosome leads to Angelman syndrome, with developmental delay, seizures and a happy demeanor. Deletion of the paternal copy causes Prader-Willi syndrome, characterized by intellectual disability and obesity.Carrying duplications in the region is a strong risk factor for autism. These duplications come in two types. Most common is 'isodicentric,' which stems from an extra chromosome and leads to two extra copies of 15q. The new study focuses on the rarer type, called 'interstitial' duplication, which occurs within a chromosome and results in just one extra copy of the region.Read more at...SFARI.org, April 2013.