June 1st, 2013

Autism linked to grandfathers

A Swedish study links a child’s autism to his/her grandfather’s age at the time their grandchildren were born.

The research conducted by Avi Reichenberg, Ph.D. and Andrew Adesman, M.D., concluded that men who fathered a child at the age of 50 or older were more likely to have a grandchild with autism, suggesting that the risk may be passed down through successive generations.

Men who fathered a son at the age of 50 or older had a 67 percent higher risk of having a grandchild with Autism Spectrum Disorder compared to men who fathered a child as young adults.

“These findings expand the time period in which exposures might contribute risk,” Autism Speaks Senior Director Alycia Halladay, Ph.D. says. “Traditionally, research has focused on prenatal factors. With these new research findings, it is clear that pre-conceptional exposures may be important as well. While the mechanism of these risk factors has not yet been fully explained, they are likely the result of epigenetics,” Halladay says.

According to William Ahearn, Ph.D., director of research at The New England Center for Children, Inc., most research suggested the paternal age as more relevant to risk factors than the age of grandfathers.

“We’ve found that the more advanced the paternal age is linked to autism in children,” Ahearn says. “Grandparents are a novel idea.”

Ahearn says mothers have a higher risk with an advanced age when the father was younger and vice versa.

The new study comes at the same time the U.S. Centers for Disease Control and Prevention announced that one in every 50 U.S. school children now has this disorder – up from the 2007 estimate. The CDC says improved detection and diagnosis are probably responsible for most of that increase.

Ahearn says autism is not like Down’s Syndrome with a clear genetic path from parent to child, noting that autism is more complex.

He says the study is nothing to worry about when planning for a family.

“In the grand scheme of things, the risk is greater (if grandfather’s age is older), but the likelihood is small overall,” Ahearn adds.

By Greg Hitchcock

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