•  The results obtained from the paternal sperm samples analysed show an accuracy of 90%
• Previous studies have already shown that children can inherit a significant predisposition to this disorder from their parents and that men have a greater influence than women on their children's risk of autism

The incidence of autism spectrum disorder (ASD), commonly known as autism, has increased dramatically in recent years. In Spain, there are currently more than 450,000 cases diagnosed. Although improvements in diagnosis and increased awareness may explain some of this change, many researchers attribute the increase over the past two decades to molecular factors and environmental influences.

In this sense, the study entitled "Sperm DNA Methylation Epimutation Biomarker for Paternal Offspring Autism Susceptibility", recently published in the journal Clinical Epigenetics in XDATE, shows how biomarkers identified in human sperm could indicate a male’s predisposition to conceive children with autism.

“These biomarkers are epigenetic, which means that they involve changes in the molecular factors that regulate the genome activity, such as gene expression, independent from the DNA sequence, and in some cases would not only cause autism in the offspring, but could also be passed on to future generations”, explained Dr. Nicolás Garrido, Director of IVI Foundation and author of the study.

Researchers have identified a set of specific biomarkers within so-called “DNA methylation regions” –a chemical alteration that occurs when a methyl group attaches to a DNA strand and can turn genes on or off– in sperm samples from men whose children had autism spectrum disorders, different from those of men who conceived children without ASD.

In a second phase, based on these characteristics, they have been able to determine which sperm samples among a set of problem samples, in a blind study, came from parents of autistic children, obtaining results with 90% accuracy, to demonstrate the predictive capacity of the test.

“In the future, this will allow us to assess whether a man is at high risk of having a child with ASD, which is a huge step towards identifying the factors that can trigger this disease, as well as creating prevention strategies, given that in some cases there are treatments to correct some epigenetic disorders”, said Dr. Garrido.

In the current study, researchers at IVI, the University of Valencia and Washington State University analysed sperm epigenetics, i.e., the molecular processes that affect gene expression, in two groups of men: thirteen who had conceived children with autism and thirteen whose children did not have ASD, focusing specifically on DNA methylation. Thus, they detected 805 differential regions of DNA methylation that could potentially act as epigenetic biomarkers in parental transmission of autism.

These findings are being extended with further research and evidence that will lead to the development of a potential medical tool. For this purpose, IVI researchers, in collaboration with specialists from other countries and institutions, are already working on a more extensive study, with the intention of expanding the sample to more than 100 men.

“With further research, this biomarker would also make it possible to track how these epigenetic changes occur from the outset. We discovered years ago that environmental factors can alter the epigenetics of the sperm or egg germ line. With this tool we could perform studies on a larger population sample to determine what kind of environmental factors can cause these epigenetic changes”, concluded Dr. Garrido.