Epigenetic Changes in Sperm Predict the Likelihood of Autism Spectrum Disorder in Children

Autism spectrum disorder prevalence has increased from 1 in 5000 people in 1975, to 1 in 68 in 2014. Better awareness of the disorder and improved diagnosis can explain some of this increase, but some scientists believe that the increase may be due to molecular and environmental factors. Furthermore, studies have shown that autism can be passed down to future generations and that this transmission is higher from fathers than mothers.

Epigenetics is the study of how your diet, lifestyle and environment can cause changes that affect the way your genes work. These changes alter the physical structure of DNA, an example being DNA methylation.

Scientists at Washington State University, Valencia Clinical Research Centre and Valencia University in Spain have recently shown that DNA methylation in certain regions of DNA in sperm affect gene expression, and could possibly be used to predict autism in children.

The investigation, published in the journal Clinical Epigenetics, studied sperm epigenetics and discovered a set of genomic features, called DNA methylation regions, in sperm samples from men who had autistic children. With this information the scientists conducted a series of blind tests to determine whether they could predict which men had autistic children. The results of these tests showed that they were able to predict men who had fathered autistic children with 90% accuracy.

The authors believe that they can now potentially use this to assess whether a man is going to pass autism on to his children, stating that it is also a major step toward identifying what factors might promote autism.

The researchers examined 26 men: 13 who had sons with autism, and 13 who had children without the disorder. They discovered 805 different DNA methylation regions that they believe can potentially act as epigenetic biomarkers for a predisposition to father children with autism. In the blind tests that followed, the researchers looked at whether sperm samples had these key DNA methylation regions and correctly identified whether men had fathered autistic children in 16 of the 18 samples.

The scientists state in their paper, that although significantly more validation with larger clinical test sets is needed, the current study provides the proof of concept that epigenetic biomarkers potentially exist and may be used to diagnose that a father may have a child with a susceptibility for autism. They are currently working on a more extensive study involving over 100 men.

The authors hope that with further research, this biomarker could also be used to trace how the epigenetic changes occurred in the first place. With this tool it is hoped that larger population-based studies can be conducted to see what kinds of environmental factors may induce these types with epigenetic changes.

References:

Garrido N, et al (2021). Sperm DNA methylation epimutation biomarker for paternal offspring autism susceptibility. Clinical Epigenetics. Volume 13, Article number: 6. Available at https://doi.org/10.1186/s13148-020-00995-2.

Biomarkers in fathers’ sperm linked to offspring autism. Washington State University. Available at https://news.wsu.edu/2021/01/11/biomarkers-fathers-sperm-linked-offspring-autism/