Familial aggregation in specific language impairment.

Self-report data from the families of children participating in the San Diego Longitudinal Study of specific developmental language impairment were used to assess familial aggregation in the disorder. Families of impaired children reported higher rates of affected first-degree relatives than did families of matched controls. Significantly higher incidence of maternal and paternal childhood language and/or learning disabilities, as well as sibling disability rates, were reported. The extent to which familial aggregation reflects genetic or environmental influences in specific language disorders remains to be determined.