The study titled, "Paternal sperm DNA methylation associated with early signs of autism risk in an autism-enriched cohort," was published on April 15 in the International Journal of Epidemiology.
Autism spectrum disorder (autism) affects one in 68 children in the U.S. The cause is largely unknown, but most experts agree that autism is typically inherited, according to Johns Hopkins University. During the course of this new study, researchers didn't look in the genes themselves, rather in the "epigenetic tags" that help regulate genes' activity.
According to the University of Utah's Genetics Learning Center (not involved in the study): "Epigenetic tags act as a kind of cellular memory. A cell's epigenetic profile - a collection of tags that tell genes whether to be on or off - is the sum of the signals it has received during its lifetime."
"We wondered if we could learn what happens before someone gets autism," said Andrew Feinberg, the King Fahd Professor of Molecular Medicine and director of the Center for Epigenetics at the Johns Hopkins University School of Medicine. "If epigenetic changes are being passed from fathers to their children, we should be able to detect them in sperm," added co-lead investigator Daniele Fallin, chair 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.
Sperm is easier to harvest for testing than egg cells from women and scientists say that sperm are more influenced by environment, which could alter the epigenetic tags on their DNA. According to Johns Hopkins, "four of the 10 sites most strongly linked to the AOSI (Autism Observation Scale for Infants) scores were located near genes linked to Prader-Willi syndrome, a genetic disorder that shares some behavioral 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."
There is no current genetic or epigenetic test for autism risk. The researchers plan to study more families and assess any environmental exposures of the dads involved.