Cannabis could change autism-related genes in sperm

According to a small study, a gene specifically associated with autism appears to undergo changes in the sperm of men who use cannabis. The genetic mutation occurs through a process called DNA methylation and could potentially be passed on to future generations.

Published in the journal Epigenetics, the researchers note that the results of this study do not establish a definitive link between consumption of cannabis and autism, but the possibility of additional links and the need for urgent studies in countries that legalize the medical and/or recreational use of cannabis.

Susan Murphy, the lead author and a doctoral student, and her colleagues conducted studies using animal and human models and analyzed differences in sperm between men who use tobacco (through smoking or ingestion) and those who do not.

In previous research published in December, the researchers noted several changes in the sperm of men who smoke cannabis. The current study focuses on specific genes, particularly one called Discs-Large-Associated Protein 2, or DLGAP2. This gene is involved in neural signaling in the brain and is strongly associated with autism, schizophrenia, and post-traumatic stress disorder.

«We identified significant hypomethylation of the DLGAP2 gene in the semen of men who had used cannabis compared to the control group, as well as in the semen of rats exposed to THC compared to the control group,« said Schrott. »This hypomethylated state was also detected in the forebrain region of rats born to fathers exposed to THC, supporting the potential for intergenerational inheritance of an altered pattern of sperm DNA methylation.»

A team at Duke University has discovered a sex-based difference in DNA methylation and gene expression in human brain tissue. In both male and female brain tissue, increased DNA methylation was associated with decreased gene activity. This relationship was stronger in women and appeared to be less pronounced in men, although the reason for this remains unknown. This discrepancy was notable, given that the male-to-female ratio among individuals with autism is 4:1. There are also sex differences regarding neurobehavioral symptoms.

«It is possible that the relationship between methylation and expression is altered if the methylation change we see in sperm is passed on to offspring,» Murphy said. «In any case, it is clear that the DNA methylation region within the DLGAP2 gene, which is altered in association with cannabis use, is functionally important in the brain.»

Murphy explained that the study’s sample size was small—it included 24 men, half of whom had used cannabis and half of whom had not—and did not account for confounding factors such as diet, sleep, and exercise, but that the results should encourage further research.

«Given the growing prevalence of cannabis in the United States and the increasing number of’States that have legalized its use, »We need further studies to understand how this drug affects not only smokers but also their unborn children,« said Mr. Murphy. »There is a perception that cannabis is harmless. Further studies are needed to determine whether that is true.”