Genetic Study Reveals How Stuttering Shares Biological Roots with Other Traits

A large-scale study has demonstrated that stuttering, a speech disorder affecting over 400 million people worldwide, has a strong genetic basis. Conducted by an international team led by Jennifer Below from Vanderbilt University Medical Center and Shelly Jo Kraft from Wayne State University, the research analyzed genetic data from more than one million individuals using information from the company 23andMe. The study, published in Nature Genetics, identified 57 specific genomic regions—mapping to 48 genes—that are significantly associated with stuttering.

Stuttering is typified by sound or word repetitions, prolongations, and speech disruptions. Despite centuries of public misconceptions about its cause—ranging from unfounded ideas about childhood trauma or intelligence to overbearing parenting—these results clarify that stuttering is influenced by genetics rather than environmental or personal shortcomings. Below stated, “Rather than being caused by personal or familial failings or intelligence, our study shows that stuttering is influenced by our genes.”

The analysis included 99,776 individuals who reported stuttering and over one million controls, with sex- and ancestry-specific data evaluation followed by meta-analyses. Since stuttering typically begins in childhood, affecting boys and girls equally at onset but persisting more often in adolescent and adult males, the researchers performed separate analyses for these groups. The findings revealed that genetic signatures of stuttering differ between males and females, a difference that could relate to the higher spontaneous recovery rate seen in females.

The research team also established polygenic risk scores based on their genetic findings. While scores based on male genetic data predicted stuttering in both males and females in independent groups, those based on female data did not, suggesting potential differences in how stuttering risk persists or is remembered across sexes. 

Beyond identifying risk genes, the study found that these regions overlap with genes involved in neurological traits, as well as metabolic and cardiovascular features. Notably, the gene VRK2, strongly associated with stuttering in males, has also been linked to musicality—specifically, the ability to synchronize to a beat—and to language decline in Alzheimer’s disease. This suggests a potential shared genetic basis between speech, language, and musical ability, challenging the traditional view that these are separate biological systems.

The research provides a scientific basis for reducing stigma, clarifying misunderstandings, and supporting early intervention for those who stutter. “Our study found that there are many genes that ultimately contribute to stuttering risk, and we hope to use this knowledge to dispel stigma related to stuttering and also to hopefully develop new therapeutic approaches in the future,” co-author Dillon Pruett added.