Older grandfathers could relay autism risk
The explanations for what causes autism have ranged from grass fertilizer to vaccinations to the father’s age. Now research published in JAMA Psychiatry has found a potential genetic connection to grandfathers—specifically men who fathered children when they were middle-aged.
The study looked at 6,000 people with autism and more than 30,000 others who did not have the condition, recording the ages of both parents and grandparents of each individual, Men who had a daughter when they were 50 or older were 1.79 times more likely to have a grandchild with autism than men who fathered children when they were between 20 and 24.
Men who fathered a boy when they were 50 or older were 1.67 times more likely to have a grandchild with the condition than younger fathers were.
The results of the study reflect a genetic component to the equation – what scientists call "silent mutations." These mutations may build up in subsequent generations and possibly interact with environmental factors, increasing the chance of autism in future generations. Though this study is being received with caution by the autism community, it could shed some light on what remains a largely mystifying condition.