In a study led by clinical director Dr. Raphael Bernier of Seattle Children’s Autism Center and Associate Professor at the University of Washington, a mutation of the CHD8 gene that not only significantly increases a child’s risk for developing a specific subtype of autism but also causes several physical traits and symptoms unique to children of the same subtype has been discovered.
Subtle physical traits such as larger heads and prominent foreheads, along with the confirmation of a CHD8 gene mutation, could allow for clinicians to screen babies still in utero for a higher risk of developing autism, similar to the screening done for Down’s syndrome.
The study, “Disruptive CHD8 Mutations Define a Subtype of Autism Early in Development,” evaluated 6,176 children with autism spectrum disorder for 9 months. Fifteen children with a CHD8 mutation all showed similar physical characteristics as well as issues with sleep disturbance and gastrointestinal problems (eg, constipation). Findings were confirmed by disrupting the CHD8 gene in zebrafish. The fish with the disrupted CHD8 gene developed large heads, wide set eyes, and were found to be constipated. These results supported that the physical features and constipation in this subgroup of individuals with autism were linked to the CHD8 mutation.
This is the first time researchers have shown a definitive cause of autism to a specific gene mutation. A previously identified gene mutation, Fragile X, is more often linked to intellectual disability than autism. The researchers hope that early detection of this gene mutation can allow for early intervention to lessen or prevent symptoms from further development.
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