Genetic instructions in paternal sperm linked to development of autism in infants. Photo by Sebastian Kaulitzki/Shutterstock
BALTIMORE, April 15 (UPI) -- Could the specifics of a father's sperm offer clues to the causes of autism? Researchers at John Hopkins Medicine say yes.
Because most instances of autism are believed to be inherited, scientists thought it might be prudent to look at the earliest of genetic instructions -- the working manual inside paternal sperm.
"We wondered if we could learn what happens before someone gets autism," Dr. Andrew Feinberg, lead researcher and director of the Center for Epigenetics at the Johns Hopkins University School of Medicine, said in a press release.
"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, a mental health professor at the Bloomberg School of Public Health and director of the Wendy Klag Center for Autism and Developmental Disabilities.
They were right. In analyzing the DNA from the sperm of fathers of children exhibiting early signs of autism, researchers identified distinct epigenetic tags that may cause or contribute to the condition.
Epigenetic tags are the instructions embedded in the genome; they help influence gene expression and regulate gene activity.
To conduct their analysis, sperm was first collected from 44 fathers as part of an ongoing study into the earliest genetic influences on a child's development. Researchers identified more than 4,500 points of interest on the genome. They then compared these points -- whether certain epigenetic tags were present or not -- to infants' placement on the Autism Observation Scale for Infants.
Researchers found 193 genomic locations were correlated with AOSI scores, suggesting certain epigenetic tags may influence the development of autism. Many of these sites were near genes related to neural development. Some of the epigenetic patterns were also found in individuals with autism, suggesting a link.
Researchers also found that four of the 10 sites most strongly correlated to AOSI scores were near genes linked to Prader-Willi syndrome, a genetic disorder that shares some symptoms with autism.
Feinberg, Fallin and their colleagues plan to follow up their investigation with larger studies. They hope more expansive studies will allow them to observe external factors and environmental conditions that might influence a father's risk of passing on autism.
The study was published in the International Journal of Epidemiology.