Recently identified genes so specific to autism they hold diagnostic potential

March 13, 2017

The recent identification of new genetic variants associated with autism brings to the forefront important considerations when using genetics as a tool for detection of this complex disorder. 

“Whole genome sequencing resource identifies 18 new candidate genes for autism spectrum disorder”—which was funded by Kids Brain Health Network and published in Nature Neuroscience—is the largest whole genome study of autism to date. The findings have implications for children and families as they represent another step towards the development of a genetic diagnostic for ASD.

“What’s being considered now is if there are some genetic findings that are so specific to autism, they could actually contribute to predictive or even diagnostic testing,” says Dr. Lonnie Zwaigenbaum. “With disorders like autism, parents are often looking for answers so even if it doesn’t guide immediate treatment, for some parents it provides some closure.”

Developing a clearer understanding of ASD’s genetic origins will ideally lead to earlier detection and help to ensure parents are able to access resources as early on in their child’s life as possible in order to improve day-to-day care. Yet at this time, only 25% of cases can be attributed to a genetic factor.

Current diagnostic practice still relies on clinical assessment, which includes talking to parents and gathering information about the child’s behavior in various settings. Clinicians may also order genetic testing, but at this point definitive genetic results are “more of a possibility than a reality,” according to Zwaigenbaum.

Co-author of a February 2017 report focusing on sharing research-based results of genetic testing related to neurodevelopmental disabilities, Zwaigenbaum says that the research community is very much focused on the principle of providing results from research if they have immediate clinical implications. At the same time "researchers avoid sharing information that doesn’t have clinical implications because of various risks, like parents feeling guilt or blame,” says Dr. Zwaigenbaum.

There is also an argument for disclosing results regardless of their immediate clinical importance. Researching and writing the collaborative report “Returning genetic research results in neurodevelopmental disorders,” along with Kids Brain Health neuroethicists, enabled the investigators to explore this grey area. 

“I think what we are seeing emerge is a more participatory framework, where parents want the information to be shared with them and then they can decide what to make out of it,” says Dr. Éric Racine, co-author of the report.  “One of the main arguments for doing this is to simply respect people who want to know and find appropriate ways of communicating this information with them.”

“Over the past decade we’ve seen a more participatory paradigm of research ethics and thinking much more of research participants and stakeholders as being active instead of just being research subjects,” says Dr. Racine. “While acknowledging that research will never be health care service, we can bridge this gap by infusing a bit more of this participatory perspective into research.”

This reflection comes at a time when important discoveries in ASD genetics are accelerating, thanks in part to the research platform used in the identification the 18 new autism-linked genes. “It’s very exciting,” says Dr. Zwaigenbaum. “By making large amounts of data broadly accessible to the scientific community, we can harness global expertise and creativity to actually look at the genetic architecture of autism, and hopefully come up with new insights about causes and possible treatments.”

The recent discovery of additional candidate genes is an important part of this progress, according to Zwaigenbaum. “It adds to the growing understanding of the biology of autism and seeing how it relates to other genes,” he says, “and really fuels research aimed at developing biological treatments.” 

Whole genome sequencing resource identifies 18 new candidate genes for autism spectrum disorder Nat Neurosci. 2017 Mar 6. doi: 10.1038/nn.4524. [Epub ahead of print]