Pedigree analysis of children with phonology disorders.

This study examined 87 pedigrees of individuals with histories of preschool phonology disorders. Results confirmed previous reports that speech and language disorders aggregate in families, with a higher incidence of males affected than females. Significantly more family members with dyslexia and learning disabilities, but not stuttering or hearing impairment, were found in pedigrees of individuals with phonology disorders than in pedigrees of nondisabled individuals. Probands with and without additional language problems did not differ in the incidence of affected family members. Nuclear family members demonstrated a higher incidence of disorders than when all family members were considered, with brothers of probands most often affected. Pedigrees of female probands had more affected members in their nuclear families than pedigrees of male probands.