How Sperm May Be Related to Autism Diagnoses

Sperm, epigenetics, & autism
Autism: Subtle, serious, social…sperm (Courtesy: Dan McGowan

You see the headlines, “Autism increased tenfold,” “Autism 1 in 2 by 2025,” and you wonder if it’s really true and why. Well, the fact is that autism rates are increasing among children. In the 1970s, autism spectrum disorder was reported in 1 in 5,000 children. In 2009, it was 1 in 110. Currently, about 1 in 54 children are identified with the condition. As you may know, I am a big fan of sperm. I’ve worked with it daily for a quarter of a century to make babies for thousands of couples when it just wasn’t happening. But now it looks like men’s sperm are part of the autism problem.

Those with autism spectrum disorder (ASD) can have difficulty communicating and interacting with others (40% do not speak), show restricted interests, and tend to exhibit repetitive behaviors. Not all those with ASD will show all of these behaviors, but most show several. Initially, it was thought that improved diagnostics and increased awareness explained the rise in ASD rates. However, over the last 20 years, leading indicators suggest that environmental, nutritional or genetic factors may be playing roles as well. And, it looks like older dads might be one of the biggest culprits.

Sperm Have Signatures

Apparently, sperm have a dark side too. We’ve reviewed the risks that older dads bring to bear on their offspring, which of course occurs through sperm. It now appears that many of these risks are not conveyed genetically (through mutations) but actually epigenetically. In other words, risk to offspring doesn’t always occur through changes to the DNA code itself as postulated by Charles Darwin, but can also occur in the way that DNA is marked to turn genes on or off. Indeed, when it comes to autism, a strong epigenetic signature has been found in the sperm of dads with affected children.

Sperm Signatures Matter

A recent study examined sperm epigenetic patterns in fathers from families with or without autistic children. Fathers from both groups donated semen samples and their sperm epigenetic patterns were compared. Over 95% of the entire sperm genome was examined for epigenetic signatures, with a focus on looking for differences between fathers with and without autistic children. Importantly, semen quality did not differ between the two groups of fathers.

The study found 805 different DNA methylation regions that were considered epigenetic biomarkers of men more likely to have children with autism. To test whether these markers could predict whether a man would have a child with autism, the researchers examined sperm from 18 men and were able to predict this with 90% accuracy. That’s a small group but a very powerful result.

Looking forward, if a sperm test could tell us the risk of autism in children, it could lead to earlier treatment which might improve the quality of life of affected children. This is similar to knowing one’s cancer risk and getting screened earlier; it’s information that packs a serious punch. And so it appears true with sperm that knowing before you go can often make the going easier.