Is there a connection between autism, Prader-Willi syndrome, Catatonia, and GABA?

Research advances in autism, Prader-Willi syndrome, and catatonia allow new inferences about their mutual relations. Catatonia has been described in both people with autism and Prader-Willi syndrome, but remains unaccounted. Although autism and Prader-Willi syndrome have been considered entities In their own right, clinlical observations suggest common ground and point to GABA dysfunction as a putative shared risk factor. The knowledge base on GABA abnormalities in autism, Prader-Willi syndrome, and catatonia is limited but expanding, and is summarized in this chapter. Preliminary findings that plasma GABA is a familial marker of autism are presented. Future research avenues are outlined.