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Thursday, September 1, 2011

Older Fathers and Autism

Tia Ghose writes at The Scientist:

While women have long been told that fertility drops off as they age, men may have a biological clock as well. The offspring of older male mice have several copy number mutations in gene regions associated with developmental disorders, according to a new study publishing today (August 30) in Translational Psychiatry. The findings could explain why the children of older men have higher rates of schizophrenia and autism than those with younger fathers.

“This study is so important,” said Dolores Malaspina, a translational neuroscientist at the New York University Langone Medical Center, who was not involved in the study. Researchers have been reluctant to believe that mutations in sperm from older men could lead to developmental disorders, she said, and studies like this could go a long way towards convincing skeptics.

In 2006, Malaspina and her colleagues studying an Israeli cohort found children of men over the age of 40 were almost 6 times more likely to have autism than those with fathers younger than 30. Other studies have shown that people suffering from schizophrenia and autism had a more copy number mutations, where a stretch of DNA is missing or replicated, than those without the disorders. But it wasn’t clear whether advancing paternal age led to these mutations, or if the mutations were the cause of the disorders, said John McGrath, a psychiatrist and epidemiologist at the Queensland Brain Institute, at the University of Queensland in Australia.