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Advanced grandparent age linked to autism risk

Grandparent age may be associated with increased risk for autism for grandchildren and suggests autism can develop over generations, according to new research.

“Analyses adjusted for the child’s birth year and sex revealed a statistically significant association between older grandfathers and autism on both the maternal and the paternal sides,” Emma M. Frans, MSc, of the Karolinska Institutet in Stockholm, and colleagues said. “The risk of autism increased monotonically with advancing grandpaternal age.”

The population-based, multigenerational, case-control study included individuals born in Sweden since 1932. Men aged at least 50 years when fathering a daughter were 1.79 times (95% CI, 1.35-2.37) more likely to have a grandchild with autism and 1.67 times (95% CI, 1.35-2.37) more likely when fathering a son vs. those fathering children when they were aged 20 to 24 years.

However, the researchers found no significant risk when age of maternal grandmother was examined.

Frans and colleagues said the findings are consistent with mutations and epigenetic alterations related to advancing paternal age.

With the increasing age of parents, the occurrence of paternal age-related disorders also will increase over time, according to the researchers.

“Our findings provide new information about the paternal age effect and its effect on future generations,” the researchers wrote. “Older men should not be discouraged to have children based on these findings, but the results may be important in understanding the mechanism behind childhood autism and other psychiatric and neurodevelopmental disorders.”

Disclosure: The study was supported by the Swedish Research Council, Swedish Council for Working Life and Social Research and the Karolinska Institutet.