The Early Autism Risk Longitudinal Investigation (EARLI) is a unique, long-term prospective study of prenatal autism spectrum disorder risk factors and markers. Launched in 2008, the EARLI study is one of the most extensive ongoing epidemiologic studies to understand the complex causes of autism. The study follows hundreds of mothers who have previously had a child with autism, from the start of a subsequent pregnancy through delivery. Researchers have followed these children through age three to assess behaviors indicative of autism and to identify any associated environmental factors. A new grant that makes EARLI part of the National Institutes of Health’s signature Environmental Risk of Child Health Outcomes (ECHO) initiative will bring back the children for additional follow-up at older ages.

Findings from the first round of analyses of EARLI data are now being published. Follow our series of blog posts to find out what EARLI data has told us about the causes of autism so far.

What dad’s sperm tells us about his child’s risk of autism

Can biochemical changes to the genes in a dad’s sperm increase the risk of autism in offspring? Researchers examined DNA methylation, a tool used by cells to turn genes on and off by adding a methyl group to specific places on a strand of DNA, in semen samples from the EARLI study to learn more. They found 193 regions in paternal sperm that were associated with early signs of autism in 1-year-old offspring. Some of these regions were also associated with genes linked to Prader-Willi syndrome – a complex genetic condition with symptoms including intellectual impairment and learning disabilities. This research suggests that these biochemical changes – which are different than the sequence of the amino acids that make up our genetic code and, very importantly, can be altered by environmental influences —may indeed contribute to autism risk.

The full article is available through PubMed.