Brett Smith for redOrbit.com – @ParkstBrett
A new study published in the journal Nature Genetics has found that mothers without symptoms of autism may pass on genetic risk factors for the developmental condition to their sons.
The study included genetic information from nearly 2,400 children with autism and by examining families with one child with autism and one or more children devoid of the condition, the scientists gathered new data on how various kinds of mutations impact autism risk.
The researchers said their genetic information was acquired from exome sequencing, which looks at just the protein-coding parts of the genome.
“The ability to examine these two types of genetic variation in exome sequencing data is the first step toward obtaining a more complete genetic picture at an individual level in the context of autism,” noted the study team, from the University of Washington and Baylor College of Medicine, in a statement.
Focusing on other mutations
Past research has focused on de novo mutations, or mutations that show up in the child but not in either parent. Some cases of autism can be linked to these mutations, but not all.
Instead of focusing on de novo mutations, the study team focused on other kinds of mutations, including those inherited from the mother or father. In particular, they quantified the autism risk of passed down gene mutations that cut off the formation of proteins. They were especially interested in those proteins that are generally unscathed in the volunteers unaffected by autism.
The scientists learned that the effect was most powerful when they detected mutations transmitted from mothers to sons. This observation suggests a female may harbor such mutations without establishing autism, but when the mutations are passed along to her male offspring, the boys are at risk of developing the condition.
The study also supplied one of the most vibrant genetic pictures of autism to date. The scientists were able to compare both small mutations of single base-pairs in DNA and larger deletions and duplications of the genome.
“These findings are a major advance in understanding the genes that play a role in autism,” said study author Raphael Bernier, associate professor of psychology and behavioral sciences at the University of Washington. “Knowing more about these genes will set the stage for personalized medicine by allowing for targeted treatments specific to an individual. This gives parents more insight and information about their child’s condition.”
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