Sperm may hold clues about whether a man's children will be at increased risk for autism, a small study suggests.
No genetic test to assess autism risk
Autism spectrum disorder is a group of developmental problems that can cause significant social, communication and behavioural challenges, according to the U.S. Centres for Disease Control and Prevention.
The CDC estimates that one in 68 U.S. children has an autism spectrum disorder. Many experts believe that autism is usually inherited, but there is no genetic test to assess autism risk, the Johns Hopkins University researchers said in a Hopkins news release.
Read: Autism or Asperger's?
"We wondered if we could learn what happens before someone [develops] autism," said Dr. Andrew Feinberg, a professor of molecular medicine at the Hopkins School of Medicine in Baltimore.
Daniele Fallin, co-lead investigator on the study and director of Hopkins' Wendy Klag Centre for Autism and Developmental Disabilities, added that if genetic modifications are being passed from fathers to their children, it might be possible to see them in sperm.
The researchers analysed DNA in the sperm of 44 fathers of children with early signs of an autism spectrum disorder. The focus was not on genes themselves, but on "epigenetic tags" that help regulate genes' activity.
The team identified 193 sites where the presence or absence of an epigenetic tag was related to autism. Many of the genes near these sites were involved in brain development.
Four of the 10 sites most strongly linked to autism were located near genes associated with Prader-Willi syndrome, a genetic disorder that causes some of the same behavioural symptoms as autism, the study authors said.
In addition, several of the altered epigenetic patterns were found in the brains of people with autism, which supports the theory that they might be related to autism, the researchers pointed out.
Occupations and environment of fathers
The study was published online in the International Journal of Epidemiology.
The Hopkins team plans to pursue these preliminary findings with a study of more families and to examine the occupations and environmental exposures of the fathers.
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