Peripheral nerve demyelination caused by a mutant Rho GTPase guanine nucleotide exchange factor, frabin/FGD4

The disruption of frabin/FGD4, a guanine nucleotide exchange factor (GEF) for the Rho GTPase cell-division cycle 42 (Cdc42), has caused peripheral nerve demyelination in patients with autosomal recessive Charcot-Marie-Tooth (CMT) neuropathy. Fabrin's ability to induce Cdc42-mediated cell-shape changes in transfected Schwann cells has indicated that Rho GTPase signaling is necessary for proper myelination of the peripheral nervous system.