Focal segmental glomerulosclerosis (FSGS) associated with type C virus (HCV) hepatitis has not been described in the literature to date. However, we experienced a 30-year-old man, who had had HCV hepatitis, developed nephrotic syndrome and was admitted to our hospital . The first renal biopsy showed FSGS which was diagnosed by light, immunofluorescent, and electron microscopic study. FSGS diagnosis was based upon the findings of focal segmental glomerular sclerosis associated with hyalinosis and foamcells, segmental deposition of IgM and C3 on glomeruli, and epithelial cell vacuolization in the Bowman's space. HCV hepatitis was treated with interferon -α (INF-α ) over 6 months. The treatment brought the disappearance of not only HCV-RNA from the blood, but also the manifestation of nephrotic syndrome. Therefore, the second renal biopsy was performed, but did not reveal any great pathological improvement. Five months later after the remission, he again had an elevated HCV-RNA level and a relapse of nephrotic syndrome. He was retreated with the same therapy and achieved a second remission of nephrotic syndrome. FSGS associated with HCV hepatitis is described first and the implication of INF-therapy in the improvement of proteinuria is discussed.
