This gene encodes a member of Rho-specific guanine nucleotide exchange factors. Rho-specific guanine nucleotide exchange factors catalyze the exchange of GDP for GTP and activate small GTPases, which function as molecular switches in signaling. This protein specifically binds cell division cycle 42, a Rho (Ras homology) GTPase. Investigations in mouse suggest that this protein is important for skeletal mineralization and for regulating the actin cytoskeleton. In humans, mutations in this gene are associated with faciogenital dysplasia, also known as Aarskog-Scott syndrome. [provided by RefSeq, May 2013]