The sequencing, undertaken by a North American collaborative formed by autism science and advocacy organisation Autism Speaks, could provide a definitive look at the wide ranging genetic variations associated with ASD.
The collaborative’s findings, published in the American Journal of Human Genetics, include the results of tests on 99 Canadian individuals including the 32 individuals with ASD (25 males and seven females) and their two parents, as well as three members of one control family not on the autism spectrum. The results include inherited and spontaneous genetic alterations found in one half of the affected families sequenced.
"From diagnosis to treatment to prevention, whole genome sequencing efforts like these hold the potential to fundamentally transform the future of medical care for people with autism," said study co-author and Autism Speaks’ chief science officer, Robert Ring.
Genetic risk variants associated with clinical manifestation of ASD or accompanying symptoms were identified in 50% of the participants. Current diagnostic technology is able to determine a genetic basis in about 20% of individuals with ASD.
The study identified genetic variations associated with risk for ASD including de novo, X-linked and other inherited DNA lesions in four genes not previously recognized for ASD; nine genes previously determined to be associated with ASD risk; and eight candidate ASD risk genes. In addition, risk alterations were found in genes associated with fragile X or related syndromes (CAPRIN1 and AFF2), social-cognitive deficits (VIP), epilepsy (SCN2A and KCNQ2) as well as NRXN1 and CHD7, which causes ASD-associated CHARGE syndrome.
“Whole genome sequencing offers the ultimate tool to advance the understanding of the genetic architecture of autism,” concluded lead author Dr Stephen Scherer, senior scientist and director of the Centre for Applied Genomics at The Hospital for Sick Children (SickKids) and director of the McLaughlin Centre at the University of Toronto.
“In the future, results from whole genome sequencing could highlight potential molecular targets for pharmacological intervention, and pave the way for individualized therapy in autism. It will also allow for earlier diagnosis of some forms of autism, particularly among siblings of children with autism where recurrence is approximately 18%.”
The Autism Speaks initiative will ultimately perform whole genome sequencing on more than 2,000 participating families who have two or more children on the autism spectrum. The data will enable new research in the genomics of ASD.