Washington: Researchers from the University of Colorado Anschutz Medical Campus have now said that there is a largely hidden part of the human genome that has a huge impact to the severity of autism symptoms.
The discovery could lead to new insights into the disorder and eventually to clinical therapies for the condition.
Researchers found that the critical genes are a part of the genome that is so complex and difficult to study that conventional genome analysis methods have unexamined it.
In this case, the region encodes most copies of the Olduvai protein domain, a highly duplicated and highly variable gene coding family that has been implicated in both human brain evolution and cognitive disease.
The researchers, led by James Sikela, PhD, a professor in the Department of Biochemistry and Molecular Genetics at the CU School of Medicine, analysed the genomes of individuals with autism and showed that, as the number of copies of Olduvai increased, the severity of autism symptoms became worse.
Speaking about it, Sikela said, “It took us several years to develop accurate methods for studying these sequences, so we fully understand why other groups have not joined in.”
“We hope that by showing that the link with autism severity holds up in three independent studies, we will prompt other autism researchers to examine this complex family,” he added.
The Sikela lab used an independent population and developed a different, higher resolution measurement technique. This new method also allowed them to zero in on which members of the large Olduvai family may be driving the link with autism.
Though autism is thought to have a significant genetic component, conventional genetic studies have come up short in efforts to explain this contribution, Sikela said.
He added that the current study adds further support to the possibility that this lack of success may be because the key contributors to autism involve difficult-to-measure, highly duplicated and highly variable sequences, such as those encoding the Olduvai family.