By Elizabeth Foy Larsen
Why are boys four times as likely to be diagnosed with autism as girls, even when both sexes have the same genetic defects associated with the disorder? According to research done by U associate professor of psychology Nicola Grissom, the answer may have something to do with specific biological protective mechanisms that operate in girls.
While scientists have been aware for some time of a “female protective effect” against autism spectrum disorders, the reason behind the safeguard has remained a mystery. To gain insight, Grissom and colleagues from the University of Pennsylvania and the University of Iowa studied populations of male and female mice that lacked a particular section of DNA—a variation called a “genetic lesion” that is found in some humans with autism. The goal was to see how the mice differed by gender in brain function, particularly in their abilities to learn new behaviors when rewarded with food.
Female mice with the lesion were unimpaired and mastered new behaviors just as quickly as other females. Males with the lesion struggled to learn new responses, and instead preferred to perform old responses repeatedly, which Grissom told U science and research editor Deane Morrison was similar to the repetitive behavior seen in people on the autism spectrum.
Researchers hope the study will lead to more effective treatments of the disorder. The research was published in October in Molecular Psychiatry.
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