Hereditary factors in stammering

A pedigree from Hazaribagh District of Bihar (india) with 12 stammerers spread over five generations was analysed for the mode of inheritance of stuttering. A predisposition seems to be a prerequisite for its occurrence. The relative roles of heredity an environment in the expression of stammering were evaluated. Transmission appears to be by a dominant autosomal. Variable expressivity, incomplete penetrance as well as partial sex-limitation as other causes have also been considered.