FGD4 (FYVE, RhoGEF, and PH Domain Containing 4): FGD4 encodes a guanine nucleotide exchange factor that specifically activates Cdc42, a member of the Rho family of GTPases. This activation plays a key role in regulating cytoskeletal organization, cell shape, and migration. Mutations in FGD4 are associated with Charcot-Marie-Tooth disease, a disorder affecting peripheral nerves, highlighting its importance in nerve development and function....