Autism spectrum disorders affect nearly 1 in 88 children, with symptoms ranging from mild personality traits to severe intellectual disability and seizures. Understanding the altered genetic pathways is critical for diagnosis and treatment. New work to examine which genes are responsible for autism disorders will be presented at the 57th Annual Meeting of the Biophysical Society (BPS), held Feb. 2-6, 2013, in Philadelphia, Pa.
"Autism is the most inheritable of neurodevelopmental disorders," explains Rajini Rao of Johns Hopkins University in Baltimore, Md., "but identifying the underlying genes is difficult since no single gene contributes more than a tiny fraction of autism cases." Rather, she continues, "mutations in many different genes variably affect a few common pathways."
A team of scientists at Johns Hopkins and Tel Aviv University in Israel looked at genetic variations in DNA sequence in the ion transporter NHE9 and found that autism-associated variants in NHE9 result in a profound loss of transporter function. "Altering levels of this transporter at the synapse may modulate critical proteins on the cell surface that bring in nutrients or neurotransmitters such as glutamate," says Rao. "Elevated glutamate levels are known to trigger seizures, possibly explaining why autistic patients with mutations in these ion transporters also have seizures."