This gene encodes a Rho-GTPase-activating protein that promotes GTP hydrolysis of Rho subfamily members. Rho proteins are important mediators of intracellular signal transduction, which affects cell migration and cell morphogenesis. Mutations in this gene are responsible for OPHN1-related X-linked mental retardation with cerebellar hypoplasia and distinctive facial dysmorhphism. [provided by RefSeq, Jul 2008].