Risk of mental illness rises with age of father

THERE has long been evidence that children of older mothers are at risk of illnesses such as Down syndrome – now it seems having an elderly father can increase the odds of developing mental illness.

Australian researchers claim they have evidence backing suggestions that children of “older” fathers are more susceptible to schizophrenia and autism.

Epidemiologist John McGrath and his colleagues report today in the journal Translational Psychiatry that older fathers pass on a type of genetic mutation, which they develop as they age. And those mutations, copy number variants (CNVs), boost the risk of schizophrenia and autism.

“The evidence is mounting that the biological clock ticks with men as well as women,” said Professor McGrath from Queensland University’s Brain Institute.

According to Professor McGrath, it’s too early to make public health recommendations, but people should be aware that older fathers can put their youngsters at increased risk of the debilitating mental disorders.

“It’s also important because these mutations may be inherited by future generations,” he said.

The team backed its claim with experiments with a genetically identical strain of mice. They bred young dads, old dads and middle-aged “control” dads with mothers of the same age, then examined the offspring once they grew up.

“We found the offspring of older dads had significant numbers of CNVs, whereas the offspring of younger dads had none. It was a startling finding,” said Professor McGrath.

The CNVs they identified in the mice had been identified in people with schizophrenia. He said the team was “astounded” to find a CNV linked to autism.

Newcastle University molecular biologist Murray Cairns, with the Schizophrenia Research Institute in Sydney, said: “We’ve known that paternal age is a risk factor for schizophrenia and autisms and now this is a validation that it could have something to do with CNVs”.

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