Children born to older fathers may be more likely to develop autism, schizophrenia and other conditions linked to genetic mutations, new research has found.
The study, published this week in the journal Nature, found that the age at which a man fathers children determines how many mutations they inherit.
“The older we are as fathers, the more likely we will pass on our mutations,” said lead author Kári Stefánsson of deCODE Genetics in Reykjavik, Iceland, which conducted the research.
“The more mutations we pass on, the more likely that one of them is going to be deleterious,” Stefánsson told Nature.
The deCODE team compared whole genome sequences of 78 one child families, looking for mutations that were not present in either parent, which means they must have occurred in the egg, sperm or embryo.
It found that fathers passed on almost four times as many mutations as mothers, and the age of the father accounted for most of the variation in the number of new mutations in the child's genome.
The number of new mutations was found to rise exponentially with the age of the father, with a man age 36 passing on double the number of mutations as compared to a father aged 20.
While most mutations are harmless, several the deCODE team identified have been linked to autism and schizophrenia.
The study does not state that older fathers are more likely to have children affected by these conditions, but that is the implication, the article in Nature said.
Other studies have found a correlation between the father's age and the likelihood of a child being diagnosed with autism. Three papers published earlier this year found that the mutations responsible for autism are four times more likely to originate on the fathers side.