The Genetics of Stuttering

Abstract

Abstract Stuttering is a common disorder that affects the flow of speech and is characterised by uncontrollable repetitions, prolongations or interruptions in speech. The aetiology of developmental stuttering is still not well understood, however genetic studies over the past decade have made some important advances. Strong evidence for genetic factors in this disorder comes from twin and adoption studies, as well as from family studies that include measures of familial aggregation, segregation and genetic linkage analyses. However, Mendelian segregation of the disorder in families does not occur, and thus stuttering is a complex genetic disorder which poses a challenge for linkage and other genetic analyses. Nevertheless, genetic linkage studies have defined numerous loci‐carrying genes that can cause persistent stuttering, and several causative genes have recently been identified. Application of massively parallel DNA (deoxyribonucleic acid) sequencing holds the promise of facilitating the identification of genes that cause stuttering and other speech and language disorders. Key Concepts Stuttering is a disorder of the flow of speech, in which the affected individuals know what they wish to say but are unable to say it owing to uncontrollable repetitions, prolongations or interruptions in their speech. Developmental stuttering typically arises at a characteristic time during the acquisition of speech in children, and approximately 75–80% children recover, sometimes with and sometimes without the aid of speech therapy. Twin studies provide strong evidence for the involvement of genetic factors in developmental stuttering. Stuttering is a complex genetic disorder in which Mendelian segregation does not occur. Genetic linkage studies in families have defined numerous loci for persistent stuttering, and several causative genes have recently been identified.