Background: Several studies have shown that family members of children with autism have elevated rates of spoken and written speech and language problems.
Aims: This study asked whether there was also a greater rate of siblings with autism among probands with specific language impairment.
Methods & procedures: The probands in this study were 158 children with specific language impairment and 132 children with normal language status. These probands had 522 siblings who were examined for risk of autism using the Autism Behavior Checklist. Siblings found to be at risk were then examined using the Autism Diagnostic Interview--Revised and the Autism Diagnostic Observation Schedule-G.
Outcomes & results: A concentration of siblings with risk for a diagnosis of autism was found in association with probands who had poor spoken language skills. Four siblings of the 522 (0.8%) met the diagnostic standards for autism. All the probands of these siblings had spoken language scores below -1 SD and three had diagnoses of spoken language impairment.
Conclusions: These data provide additional support for a familial association between autism and spoken language impairment.