More pieces in the complex autism inheritance puzzle are emerging in the latest study from a research team including geneticists from The Children’s Hospital of Philadelphia, the University of Pennsylvania School of Medicine and several collaborating institutions. This study identified 27 different genetic regions where rare copy number variations – missing or extra copies of DNA segments – were found in the genes of children with autism spectrum disorders (ASDs), but not in the healthy controls. The complex combination of multiple genetic duplications and deletions is thought to interfere with gene function, which can disrupt the production of proteins necessary for normal neurological development.
"We focused on changes in the exons of DNA—protein-coding areas in which deletions or duplications are more likely to directly disrupt biological functions," said study leader Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children’s Hospital of Philadelphia and associate professor of Pediatrics at the University of Pennsylvania School of Medicine. "We identified additional autism susceptibility genes, many of which, as we previously found, belong to the neuronal cell adhesion molecule family involved in the development of brain circuitry in early childhood." He added that the team discovered many "private" gene mutations, those found only in one or a few individuals or families—an indication of genetic complexity, in which many different gene changes may contribute to an autism spectrum disorder.