Washington: A new research has found a full genome sequencing examining the entire DNA code of individuals with autism spectrum disorder (ASD) and their family members - a finding that could provide a definitive look at the wide ranging genetic variations associated with ASD.
The study reports on full genome sequencing on 32 unrelated Canadian individuals with autism and their families, participants in the Autism Speaks Autism Genetic Resource Exchange (AGRE).
The results include both inherited as well as spontaneous or de novo, genetic alterations found in one half of the affected families sequenced.
This dramatic finding of genetic risk variants associated with clinical manifestation of ASD or accompanying symptoms in 50 percent of the participants tested is promising, as current diagnostic technology has only been able to determine a genetic basis in about 20 percent of individuals with ASD tested.
The large proportion of families identified with genetic alterations of concern is in part due to the comprehensive and uniform ability to examine regions of the genome possible with whole genome sequencing missed in other lower resolution genome scanning approaches.
"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," Autism Speaks Chief Science Officer and study co-author Robert Ring, Ph.D, said.
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.
Some families had a combination of genes involved. 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," 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, said.
"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 percent," he added.
The study is published online in American Journal of Human Genetics.