Scientists Spot Gene Tied to Severe Autism in Girls

By Dennis Thompson HealthDay Reporter

WEDNESDAY, March 25, 2015 (HealthDay News) -- Researchers say they've discovered a new genetic cause of autism, singling out a rare gene mutation that appears to hamper normal brain development early on in powerful ways.

The gene, CTNND2, provides instructions for making a protein called delta-catenin, which plays crucial roles in the nervous system, said senior author Aravinda Chakravarti, a professor in the Johns Hopkins University School of Medicine's Institute of Genetic Medicine.

His research team found that a group of girls with severe autism carried CTNND2 mutations that appeared to reduce the effectiveness of delta-catenin, potentially affecting their neurological development.

"There are many, many proteins that in fact 'moonlight,' doing many, many different things," Chakravarti said. "Maybe the severity of the effect of delta-catenin comes from the fact that when you lose function of this protein, you lose not just one function but many functions. Although that remains to be shown, it is strongly implicated by our study."

Autism spectrum disorder is a neurological and developmental disorder that begins early in life. The cause is not known, although scientists suspect genes play a role.

The researchers discovered the CTNND2 gene's link to autism using an approach that focuses on rare and extreme cases of autism, according to the study released online March 25 in the journal Nature.

By focusing on extreme cases, they believe they will discover genes that have a more powerful effect on brain development and help explain the root causes of autism.

"If we study rare and extreme forms, they are both genetic and they represent very early neurodevelopmental events," Chakravarti said.

The researchers chose to study girls with autism because they are far less likely to have autism than boys. When girls do develop the disorder, their symptoms tend to be severe.

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Scientists Spot Gene Tied to Severe Autism in Girls