Have you ever wondered why some people stutter? You’re not alone. Developmental stuttering—disruptions in the normal flow of speech, like repeating sounds or involuntary pausing on words— affects more than 400 million people worldwide. A new genetic study, powered in part by data from more than one million consented 23andMe research participants, offers exciting insights into the genetics behind stuttering.
Stuttering Often Starts Young—And Many Kids Recover
Most people who stutter begin showing signs between ages 2 and 5. For many, it’s temporary—about 80% of children who stutter will recover, often naturally and sometimes with the help of speech therapy. Interestingly, boys and girls are about equally likely to start stuttering, but by the time they reach adulthood, men are four times more likely to continue stuttering compared to women.
The Genetics of Stuttering: A New Look
Until recently, research into the genetics of stuttering has been limited to a handful of rare genetic variants identified in families. But a new large-scale study is changing that. By combining genetic data from over a million individuals, researchers identified 57 genetic variants (in or near 48 unique genes) linked to self-reported stuttering.
Some of these genetic signals were ancestry- or sex-specific, meaning they were only significant associations in certain populations. Others were shared across groups, highlighting the complex nature of the genetics behind stuttering.
And there’s more: while most previously reported variants were too rare or not included in the dataset, this study still found strong genetic signals in three of the six candidate genes previously linked to stuttering—GNPTAB, GNPTG, and AP4E1—adding new weight to past findings.
Some of the genetic findings in this study also overlap with traits like depression, autism, and even beat synchronization (your ability to accurately synchronize your movements with a musical beat). These overlaps suggest that stuttering might share some genetic similarity with these other traits.
The Value of Diversity in Genetic Research
One important takeaway from this study is the value—and the current limits—of genetic diversity in research. Researchers were able to create a polygenic risk score (PRS) for stuttering using data from people of European descent and found that it predicted stuttering risk well in both independent clinical and self-reported datasets. However, a lack of large, diverse datasets meant that the team couldn’t validate similar scores for people from other ancestry groups.
That’s why increasing diversity in genetic studies is so important. It helps ensure that the insights we gain are applicable to everyone.
What This Means for the Future
This study marks a major step forward in understanding the genetic contribution to stuttering. It confirms that stuttering, like many other traits, is influenced by a complex mix of genetic factors. And it highlights the importance of building inclusive, diverse research databases to ensure that discoveries can benefit as many people as possible.
Whether you’ve experienced stuttering yourself, know someone who has, or are just curious about the science of speech, studies like this help us better understand the fascinating interplay between genetics and communication.
Learn more about this study from our collaborators at Vanderbilt University Medical Center and learn more about research at 23andMe.
