Genetic factors and therapy outcomes in persistent developmental stuttering

Area of Science:

• Genetics
• Speech-Language Pathology

Background:

• Persistent developmental stuttering is a complex speech disorder.
• Genetic factors are known to contribute to stuttering etiology.
• Specific gene mutations (GNPTAB, GNPTG, NAGPA, AP4E1) are associated with stuttering.

Purpose of the Study:

• To investigate if therapy outcomes for persistent developmental stuttering differ between individuals with and without known stuttering-related gene mutations.
• To compare the efficacy of an intensive fluency shaping-based therapy program based on genetic status.

Main Methods:

• A cohort of 51 individuals with persistent developmental stuttering carrying mutations in GNPTAB, GNPTG, NAGPA, or AP4E1 genes was studied.
• Outcomes were compared to 51 matched individuals without these mutations who underwent the same therapy.
• Therapy efficacy was measured using blinded observer-based quantitative stuttering dysfluency measures (Dysfluent Words Score, DWS) and self-reported measures (Perceptions of Stuttering Inventory, PSI).

Main Results:

• Intensive therapy significantly improved fluency overall for both groups.
• Mutation carriers showed significantly less improvement in self-reported speaking difficulties (PSI scores) compared to non-carriers (p=0.0157).
• While not statistically significant in this study, a trend suggested less improvement in DWS for mutation carriers, warranting further research.

Conclusions:

• Persistent developmental stuttering may be more resistant to fluency shaping therapy in individuals carrying known stuttering-related gene mutations.
• Genetic status is a potential factor influencing therapeutic outcomes for stuttering.
• Further research is needed to explore the impact of specific gene mutations on stuttering treatment efficacy.