Autism results in various mutations, even between siblings, a new study has discovered.
Autism spectrum disorder presents symptoms which are most similar among siblings sharing identical genetic mutations, the study found.
Researchers studied 85 families who each had two children diagnosed with autism. Whole-gene sequencing, which identifies mutations over entire genetic codes, was used in the study, in order to identify genetic relationships between autistic siblings.
"We anticipated that, more often than not, there would be shared inheritance. That wasn't the case," in siblings, Stephen Scherer, a geneticist at the University of Toronto, said.
The study revealed that roughly 31 percent of the siblings shared similar genetic codes, while 69 percent of the pairs did not. Around 42 percent of families in the study showed known high-risk genes for the disorder.
Several factors could contribute to autism spectrum disorder, the researchers believe. Researchers have recently found as many as 100 genes that appear to significantly raise the risk of autism. However, these mutations only account for a small percent of cases of autism. Medical researchers now believe that the disorder may be triggered by a combination of otherwise harmless gene adaptations. Future studies may need to examine tens of thousands of subjects, attempting to pin down the exact causes of the complicated disorder.
"We knew that there were many differences in autism, but our recent findings firmly nail that down. We believe that each child with autism is like a snowflake - unique from the other," Scherer said.
Autism Speaks, an advocacy group working to advance diagnosis and treatment options for those suffering from autism, sponsored the research. This was the first piece of major research ever funded by the organization.
Autism Speaks also released around 1,000 autism genomes to their Web site, powered by the Google Cloud Platform. The information in the database is anonymous, protecting the privacy of subjects examined. Managers at Autism Speaks hope to bring the database up to 10,000 subjects, providing the greatest collection of autism genomes in the world.
"The study is very well designed, the end result is somewhat surprising, and it reiterates the complexity of the underlying genetics of autism," Yong-hui Jiang of the Duke University School of Medicine told reporters.
This new finding could lead to new treatments, designed to predict a mother's risk of giving birth to a second child with the disorder after a first child is born with autism.
Discovery of the variety of genes involved with autism between siblings was detailed in the journal Nature Medicine.