Uncovering a Genetic Connection Between Autism and DM1
Scientists from The Hospital for Sick Children (SickKids) and the University of Las Vegas, Nevada (UNLV) have discovered a genetic mechanism that may help explain the development of autism spectrum disorder (ASD). Their research reveals a molecular link between ASD and a rare inherited condition called myotonic dystrophy type 1 (DM1)—a disorder that leads to progressive muscle weakness.
The findings, published in Nature Neuroscience, offer a new understanding of how certain genetic variations could contribute to the social and behavioral traits often observed in individuals with ASD.
Rare Disorder Increases Autism Risk
While ASD affects roughly 1% of the general population, the risk is 14 times higher in individuals with DM1. DM1 is caused by tandem repeat expansions (TREs) in the DMPK gene, a genetic anomaly that not only affects muscle function but also appears to disrupt normal brain development.
As per The Medical XPress, researchers now believe these TREs play a significant role in interfering with gene splicing—a key biological process that ensures genes are read and executed correctly by the body.
TREs and the Disruption of Brain Function
TREs are sections of DNA that repeat multiple times. The more often they repeat, the more likely they are to interfere with proper gene function. In this study, the researchers found that the DMPK gene’s expanded TREs generate a form of toxic RNA. This RNA binds to and depletes proteins crucial for gene splicing during brain development.
Without these proteins, mis-splicing occurs in other genes—especially those involved in brain function. This disruption likely contributes to the social and cognitive challenges associated with ASD, particularly in children who also have DM1.
Connecting the Dots: A Molecular Link
Dr. Łukasz Sznajder, Assistant Professor at UNLV and a lead researcher on the study, recalls how one specific genetic variation caught his attention.
“A variation really stood out to me that we see in rare neuromuscular diseases,” he said. “This is how we started connecting the dots. We found a molecular link, or overlap, which we believe is the core of causing autistic symptoms in children with myotonic dystrophy.”
TREs Act Like a Molecular Sponge
Dr. Ryan Yuen, Senior Scientist at SickKids, explains the mechanism in simple terms:
“TREs are like a sponge that absorbs all these important proteins from the genome. Without this protein, other areas of the genome don’t function properly.”
His team discovered that as these TREs expand, they soak up the proteins needed for gene splicing. This disruption prevents normal brain development and contributes to the behavioral outcomes associated with ASD.
Hope for Precision Therapies
Encouragingly, the research opens new possibilities for targeted treatment. The Yuen Lab and Sznajder Lab are now investigating whether this protein imbalance affects other genes associated with ASD. Their goal is to develop precision therapies that could restore these critical proteins to the genome.
In fact, researchers have already made some progress. Back in 2020, Dr. Christopher Pearson of SickKids identified a molecule capable of contracting TREs in Huntington’s disease. This breakthrough could potentially lead to similar treatments for DM1, ASD, and other related genetic conditions.
Looking Ahead
Although more research is needed, this study marks a significant step forward in understanding the genetic underpinnings of autism. By revealing how repeat expansions disrupt brain development, scientists now have a clearer path toward improving diagnosis, treatment, and long-term care for individuals affected by both DM1 and ASD.