Population-based genetic effects for developmental stuttering

Area of Science:

• Genetics
• Speech and Language Disorders
• Human Genomics

Background:

• Developmental stuttering is a common speech disorder with a significant genetic component, yet its inheritance is complex and poorly understood.
• Previous genetic studies have been underpowered, hindering the identification of specific genes contributing to stuttering susceptibility.
• Understanding the genetic basis of stuttering is crucial for developing targeted interventions.

Purpose of the Study:

• To conduct a trans-ancestry genome-wide association study (GWAS) and meta-analysis to identify genetic variants associated with developmental stuttering.
• To investigate the genetic architecture of stuttering in large, diverse populations.
• To pinpoint specific genes and pathways involved in stuttering risk.

Main Methods:

• Meta-analysis of two large datasets: The International Stuttering Project (1,345 cases, 6,759 controls) and The National Longitudinal Study of Adolescent to Adult Health (Add Health) (785 cases, 7,572 controls).
• Genome-wide association study (GWAS) analysis across diverse ancestries.
• Expression quantitative trait locus (eQTL) analysis to assess the functional impact of identified variants.

Main Results:

• Identified a genome-wide significant protective variant (rs113284510) in the SSUH2 gene associated with developmental stuttering.
• The protective variant acts as an expression quantitative trait locus (eQTL), reducing SSUH2 gene expression in esophagus-muscularis tissue.
• Discovered 15 additional loci with suggestive significance (p < 5 × 10⁻⁶), indicating potential novel genetic associations.

Conclusions:

• This study provides foundational population-based genetic insights into developmental stuttering.
• The identification of a protective variant in SSUH2 highlights its potential role in stuttering etiology.
• Further research is needed to elucidate the complex genetic factors contributing to stuttering susceptibility and to validate additional identified loci.