Study examines gene’s effect on cognitive abilities
With identical twins, if one sibling is diagnosed with an autism spectrum disorder, the other twin also will have an autism spectrum disorder more than 90 percent of the time. With fraternal twins, the likelihood of a second diagnosis is less than 10 to 15 percent.
Clearly, genes play a significant role in autism, says Thomas Frazier II, PhD, Director of Research for the Cleveland Clinic Center for Autism within the Pediatric Institute & Children’s Hospital. His next project will study the relationship between the PTEN gene and autism spectrum disorders.
PTEN is well known in cancer research as a tumor suppressor gene. When mutations occur, there is unchecked cell growth, which can lead to cancer.
But this rapid cell growth also can happen in an infant’s brain, causing the brain and skull to increase in size. Such unregulated growth results in cognitive problems, says Dr. Frazier, who received a grant from the National Institutes of Health that he will use to study a subgroup of children who have both a large head size and PTEN mutation.
About 25 percent of children with autism have a large head size; about 10 to 20 percent of those children have a PTEN mutation, he says. For the NIH project, he will work with Charis Eng, MD, PhD, who is the world’s expert on PTEN and holder of the Sondra J. and Stephen R. Hardis Chair in Cancer Genomic Medicine at Cleveland Clinic’s Lerner Research Institute.
MRI scans will help Dr. Frazier learn how PTEN mutations change the brain and what cognitive problems result. The findings could help determine the potential benefits of early childhood screening for genetic mutations and could lead to the development of medicines that would compensate for the function of PTEN.
His previous research study looked at the structural neural abnormalities in children with autism spectrum disorders. Specifically, these children have a smaller than normal corpus callosum, which connects the two sides of the brain. If the corpus callosum isn’t working properly, the two sides of the brain aren’t going to communicate correctly, Dr. Frazier says.
He has no doubt that his previous research, which was supported entirely by philanthropy, was a factor in his being chosen for the grant. “You can’t get NIH grants without really good pilot data,” Dr. Frazier says. “The only way to get really good pilot data is with philanthropic or foundation support.”
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