Genetic 'tags' may signpost autism
Scientists have found that DNA from the sperm of men whose children showed early signs of autism shows distinct patterns of "regulatory tags" that could contribute to the condition.
It is estimated one in every 100 people has autism spectrum disorder (ASD) in the UK and although most experts agree that autism is usually inherited as it tends to run in families, and studies have identified some culprit genes, it remains unexplained.
In a small study, researchers in the United States looked for possible causes for the condition not in genes themselves, but in the "epigenetic tags" that help regulate genes' activity.
The team assessed the epigenetic tags on DNA from sperm from 44 fathers who already had a child with autism and whose partners were pregnant.
One year after the child was born, he or she was assessed for early signs of autism using the Autism Observation Scale for Infants (AOSI).
After looking for epigenetic tags at 450,000 different positions throughout the genome, scientists compared the likelihood of a tag being in a particular site with the AOSI scores of each child.
They found 193 different sites where the presence or absence of a tag was statistically related to the AOSI scores.
When they looked at which genes were near the identified sites, they found that many of them were close to genes involved in developmental processes, especially neural development.
They said of particular interest was that four of the 10 sites most strongly linked to the AOSI scores were located near genes linked to Prader-Willi syndrome, a genetic disorder that shares some behavioural symptoms with autism.
Several of the altered epigenetic patterns were also found in the brains of individuals with autism, giving credence to the idea that they might be related to autism.
Professor Daniele Fallin, chairwoman of the Department of Mental Health in the Bloomberg School of Public Health and director of the Wendy Klag Center for Autism and Developmental Disabilities, said: "If epigenetic changes are being passed from fathers to their children, we should be able to detect them in sperm."
The research is published online in the International Journal of Epidemiology.