A genetic perspective on stuttering

If one considers stuttering to be one possible outcome of a developmental and learning process, it is possible to conclude, a priori, that both environmental variation and genetic variation are likely to be involved in determining those who ever stutter and those who never stutter. Proof exists of the importance of nongenetic (environmental) variation in the etiology of stuttering; no conclusive proof exists of the involvement of genetic variation. The available evidence on the familial concentration of stuttering is compatible with hypotheses that incorporate a major genetic component. According to these hypotheses, the familiality is due to genetic transmission, and the interaction of genetic predisposition with environmental factors is affected by the individual's sex. No conclusion is yet possible on the specific type of genetic transmission.