[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/szatmari.jpg” caption=”Peter Szatmari is co-principal investigator for a team of international scientists who have uncovered more key changes in the DNA of individuals with autism. File photo.”]

var addthis_config = {
data_track_clickback: true
}

The Phase 2 results of the multinational Autism Genome Project Consortium, published in the June 9 advance online edition of the high-impact journal Nature, substantiate the importance of genes as susceptibility factors in autism spectrum disorders.

The study is the largest of its kind, involving 1,500 families and more than 120 scientists and clinicians from across North America and Europe. The research team was co-led by Peter Szatmari, a professor of psychiatry and behavioural neurosciences at the Michael G. DeGroote School of Medicine, McMaster University, and Stephen Scherer, a senior scientist at The Hospital for Sick Children (SickKids). Dalila Pinto, a post-doctoral research fellow at SickKids, was lead author of the study.

Using microarrays (or gene-chip technology) in the highest-resolution testing to date, researchers investigated individuals with autism spectrum disorders (ASDs). ASDs, diagnosed in one in 110 children, are a group of neurodevelopmental conditions resulting in challenges connected to communication, social understanding and behaviour.

The researchers reported that individuals with ASDs tended to carry more insertions and deletions affecting their genes – called copy number variants (CNV) – than did people in the control group. Some of these CNVs appeared to be inherited, while others are considered new, because they are found only in offspring with autism and not in the parents. Dozens of new “autism risk genes” were discovered, including some that might be helpful in early diagnosis.

“This study will lead to a paradigm shift when it comes to our understanding of the root causes of autism and indeed other neurodevelopmental disorders,” said Szatmari, director of the Offord Centre for Child Studies at McMaster.

“Previously it was believed that autistic individuals share common genetic variations in a few genes. This research points to the fact that genetic variations are actually rare, meaning individuals with autism are genetically quite unique. But as we discover more and more of these variants, the number of cases of ASD we can explain increases substantially.”

Scherer, director of The Centre for Applied Genomics at SickKids, said: “We now know several of the genes involved in autism and for the first time, we are able to tie many of these genes into the same biological pathways involved in brain function.”

“Knowing these autism genes are linked, we can begin to develop therapies to target the common pathways involved.”

The study found that for about 10 per cent of the families studied, there are some genetic clues that may assist in the early diagnosis of autism or related complications. The Canadian researchers say the next step is to set up a way that all families can have access to this testing.

The Autism Genome Project includes 120 scientists from more than 50 institutions in 12 countries who formed a unique autism genetics consortium. The project began in 2002 when researchers from around the world came together to share their samples, data and expertise to facilitate the identification of autism susceptibility genes.

Stay connected