Older men more likely to father a child with autistic spectrum disorder

Embargoed until Wednesday, October 01, 2008

Children born to older fathers are at increased risk of having an autistic spectrum disorder (ASD), according to new research published in the October issue of the British Journal of Psychiatry.

 

But the researchers found no link between increased maternal age and the risk of ASD.

 

The study, which was carried out in Japan, involved 84 participants with ‘high-functioning’ ASD. This meant that they displayed symptoms of autism, such as difficulties with socialising, communication and behaviour, but did not have an intellectual disability (i.e. all the participants had an IQ of more than 70).

 

This group was compared with 208 healthy controls, who had no intellectual disability and had not been diagnosed with any psychiatric disorder.

 

The participants were divided into three groups, depending on how old their parents were when they were born. The three age classes were: under 29, 29-32 and over 33.

 

The researchers found that a one-level advance in the paternal age class corresponded to a 1.8-fold increase in the risk of the child having high-functioning ASD. However, there was no association between an increase in the maternal age at birth and the development of ASD.

 

Explanations for the effect are unclear, but it is thought that mutations can occur in the paternal germ line as the father gets older. Mutations in sperm can then be passed on to children.

 

This is the first study to explore the effect of paternal age on the risk of high-functioning ASD. Its findings correspond with previous studies which have shown a link between older fathers and a low IQ in children.
© 2008 Royal College of Psychiatrists