The HOPA gene dodecamer duplication is not a significant etiological factor in autism

A recent study has suggested that a dodecamer duplication in the HOPA gene in Xq13 may occur in a significant portion of male patients with autism. We have determined the incidence of this duplication in 202 patients from the South Carolina Autism Study. The incidence of the duplication was not sign ificantly different between patients and controls. Three of the female pati ents inherited the duplication from nonautistic fathers. In addition, there was no systematic skewing of X inactivation in the female patients with th e duplication, or in nonautistic mothers and sisters with the duplication. These findings suggest that the dodecamer duplication in the HOPA gene does not play a significant role in the etiology of autism.