Mutations such as MYO9A (a Rho-GTPase activating protein myosin) (66), MYO1E (nonmuscle class I myosin, myosin 1E) (67), INF2 (a member of the formin family of actin-regulating proteins INF2) (68), DAMM2 (a member of the formin family of actin-regulating proteins DAAM2) (69), ACTN4 (alpha-actinin 4) (70), CD2AP (CD2-associated protein) (71), and ANLN (filamentous actin [F-actin] binding protein) (72) have been identified in patients with nephrotic syndrome and histological evidence of focal segmental glomerulosclerosis (FSGS). The gene discussed is ACTN4; the disease is nephrotic syndrome.