Autism is a complex disease characterized by wide variety of factors on a spectrum. A new study published in the July 20th issue of the journal Nature Genetics, determined that 52% of autism cases is correlated to common genes and rarely inherited variations. The exact cause for autism remains unknown with environmental and genetics factors blamed.
The research team analyzed the statistics occurrence of genes and their relation to autism. The data was obtained from Sweden’s universal health registry which included 3000 subjects and contained both autistic subjects and a control group. New statistical methods were used to evaluate the inheritability of autism. In addition, they were able to compare their results with a parallel family-based study in the Swedish population, which took into account data from twins, cousins, and factors like age of the father at birth and parents’ psychiatric history.
“From this study, we can see that genetics plays a major role in the development of autism compared to environmental risk factors, making autism more like height than we thought — many small risk factors add up, each pushing a person further out on the spectrum,” said Roeder, professor of statistics and computational biology at Carnegie Mellon and a leading expert on statistical genomics and the genetic basis of complex disease.
“These findings could not have happened without statistics, and now we must build off of what we learned and use statistical approaches to determine where to put future resources, and decide what is the most beneficial direction to pursue to further pinpoint what causes autism.”
“Thanks to the boost in statistical power that comes with ample sample size, autism geneticists can now see the forest for the trees,” said Thomas R. Insel, director of the National Institute of Mental Health (NIMH). “Knowing the nature of the genetic risk will help focus the search for clues to the molecular roots of the disorder.”
“Within a given family, the mutations could be a critical determinant that leads to the manifestation of ASD in a particular family member,” said Joseph Buxbaum, the study’s first author and professor of psychiatry, neuroscience, genetics and genomic sciences at the Icahn School of Medicine at Mount Sinai (ISMMS). “The family may have common variation that puts it at risk, but if there is also a ‘de novo’ mutation on top of that, it could push an individual over the edge. So for many families, the interplay between common and spontaneous genetic factors could be the underlying genetic architecture of the disorder.”
The study for the first time has developed a possible genetic model for autism.
Trent Gaugler, Lambertus Klei, Stephan J Sanders, Corneliu A Bodea, Arthur P Goldberg, Ann B Lee, Milind Mahajan, Dina Manaa, Yudi Pawitan, Jennifer Reichert, Stephan Ripke, Sven Sandin, Pamela Sklar, Oscar Svantesson, Abraham Reichenberg, Christina M Hultman, Bernie Devlin, Kathryn Roeder, Joseph D Buxbaum. Most genetic risk for autism resides with common variation. Nature Genetics, 2014; DOI: 10.1038/ng.3039