Unravelling the genetic basis of stuttering: GWAS meta-analysis highlights link with rare speech disorders
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Background
Developmental stuttering affects up to 11% of children globally, with around one-fifth developing a persistent lifelong stutter. Twin and family studies indicate a strong genetic contribution and comorbidity with other heritable traits. Despite efforts to investigate the common genetic architecture of stuttering, much of variation contributing to clinically ascertained stuttering, persistence and recovery remains uncharacterised.
Methods
We performed a genome-wide association study (GWAS) meta-analysis of stuttering across 18 cohorts (6,096 cases, 81,629 controls) of European ancestries, with secondary analyses of stuttering persistence and sex-stratified GWAS.
Findings
No variant reached genome-wide significance in the primary meta-analysis, but 24 loci showed suggestive association (p<1×10⁻⁵), with SNP-based heritability estimated at h²≈0·26. FLAMES-prioritised genes at suggestive loci overlapped with those previously implicated in childhood apraxia of speech, including PTBP2 , KIRREL3 , CAMTA1 , GRIN2A , and SETBP1 , with significant enrichment for apraxia-associated genes overall (p=1×10⁻⁴). Meta-analysis with an independent self-reported stuttering GWAS identified a genome-wide significant association at MPPED2 and gene-level convergence at CAMTA1 and PTBP2 . A polygenic risk score derived from this independent GWAS was associated with stuttering susceptibility and severity within clinically ascertained cases. Partitioned heritability analysis pointed to enrichment in conserved regulatory regions, and integration with imaging data highlighted motor circuitry including decreased pallidum volume and cerebellar and white-matter microstructural differences.
Interpretation
Our findings support common variant associations in stuttering converging on genes implicated in speech and neurodevelopmental conditions, pointing to basal ganglia–cerebellar motor circuits as central to speech motor control.
Funding
Australian National Health and Medical Research Council.
Research in context
Evidence before this study
We searched PubMed for genome-wide association studies (GWAS) of stuttering, using terms including “stuttering,” “stammering,” and “genome-wide association,” for studies prior to July 2026, with no language restriction. Prior GWAS of stuttering are limited. The International Stuttering Project combined clinically ascertained and self-reported cases with population controls and identified one genome-wide significant locus near SSUH2 and 15 loci at suggestive significance. Another study investigating predicted stuttering within Vanderbilt’s Electronic Health Records, identified one locus surpassing genome-wide significance near CYRIA . A larger GWAS using self-reported stuttering status identified 57 genome-wide significant loci. Twin and family studies estimate stuttering heritability at 0·42–0·85, and rare variant studies have implicated genes including GNPTAB , GNPTG , NAGPA , AP4E1 , PPID , and ZBTB20 in familial persistent stuttering, but it remains unclear whether these genes are also relevant to common genetic variation in the general population.
Added value of this study
We conducted the largest GWAS meta-analysis of stuttering to combine clinically ascertained cases with population-based cohorts, comprising 18 cohorts, 6,096 cases, and 81,629 controls. Unlike prior studies based solely on self-report, many of our ascertained cases had detailed phenotyping including measures of persistence and quantitative severity, allowing us to examine genetic overlap between stuttering onset, persistence, and severity. We identified suggestive genetic loci that converge with genes previously implicated in a rare, severe motor speech disorder (childhood apraxia of speech), and found that combining our data with the independent, previous GWAS of self-reported stuttering identified a genome-wide significant association. We further used imaging genetics approaches to link genetic risk for stuttering to specific brain regions and circuits involved in motor control, and used evolutionary genomic analyses to show that stuttering-associated regions are enriched in ancient, conserved parts of the genome.
Implications of all the available evidence
Our findings suggest that common genetic variation contributing to stuttering converges on the same genes and brain circuits implicated in rare, severe speech disorders. This strengthens the case that stuttering, at least in part, shares a biological basis with other neurodevelopmental and speech-motor conditions, and points to the basal ganglia– cerebellar motor circuit as a promising target for future mechanistic research. For clinicians and people who stutter, these findings do not yet have direct treatment implications, but they lay groundwork for better understanding why stuttering persists in some individuals and not others, and highlight the value of collecting detailed speech and language phenotypes in future large-scale genetic studies.
