Science and discovery has come a long way since autism was first identified in the 1940s, according to The National Autistic Society. Yet there is still no cure for the complex brain development disorder that causes varying degrees of difficulty in social interaction, verbal and nonverbal commination, and repetitive behavior. While clues for the cause have been largely investigated during pregnancy, Johns Hopkins researchers set out to see if the father’s sperm had any answers.

"If epigenetic changes are being passed from fathers to their children, we should be able to detect them in sperm," said the co-lead investigator Dr. Daniele Fallin, director of the Wendy Klag Center for Autism and Developmental Disabilities. The study, which was published in the International Journal of Epidemiology, revealed distinct patterns in DNA from the sperm of men who had children showing early signs of autism.

Most experts agree there is a hereditary component at works when a child develops autism in the womb, according to the researchers. Fallin and her research team studied the epigenetic tags from the DNA found in 44 fathers’ sperm. Epigenetics is an increasingly common study of physiological trait variations by which genes can be switched on and off on a cellular level. One out of every 68 children born today have autism, and prevalence rates are growing, according to Autism Speaks. It was important to the researchers to investigate a group of fathers that had children who were not yet diagnosed with autism in order to see the earliest genetic influences.

"We wondered if we could learn what happens before someone gets autism," the study’s co-lead author Dr. Andrew Feinberg, director of the Center for Epigenetics at the Johns Hopkins University School of Medicine, said in a press release.

Early on in the pregnancy, a sperm sample was collected from fathers before they even knew if their child was at risk for diagnosis or not. After the child’s first birthday, he or she was assessed for early signs of autism using the standardized Autism Observation Scale for Infants. The research team then combed through the 450,000 different positions in each father’s DNA sperm sample. They then compared the presence or absence of certain genetic markers and lined them up with who had a child with early signs of autism. They found 193 different markers for similarities in the fathers’ DNA linked to their child.

More importantly, those same genes were ones intimately involved in the developmental process of a baby. Of particular interest was the unexpected link between where those genes were located, researchers said. The genetic markers connecting a father’s DNA to their child with early signs of autism were located near genes linked to Prader-Willi syndrome.

There are similar behavioral symptoms between children with autism and those with Prader-Willi: Both are born with signs and suffer from physical, mental, and behavioral problems, according to the Mayo Clinic. A symptom unique to Prader-Willi is the insatiable sense of hunger experienced by a child as early as 2 years of age. Increasingly, researchers are finding connections between autism and gastrointestinal issues, according to the Autism Research Institute. Researchers will continue to explore the paternal role in autism development in addition to discovering specific environmental factors.

Source: Fallin D and Feinberg A. International Journal of Epidemiology. 2015.