INF2 and focal segmental glomerulosclerosis: Formins are a multigene family of proteins with diverse abilities to regulate cellular functions involving actin and microtubule cytoskeletal networks.1, , –4 Mutations in INF2 are a major cause of familial and sporadic cases of autosomal dominant FSGS, as well as non-FSGS types of podocytopathy with poor medical response and clinical prognosis.5, –7 Despite many studies investigating the mechanism of INF2 mutations in causing FSGS,4,8, , , –12 the mainstay of therapy, renin-angiotensin II-aldosterone blockage, has not improved the unfavorable outcome of the disease.