IgM nephropathy associated with familial Mediterranean fever.

Three patients with a long-standing history of familial Mediterranean fever (FMF) were found to have both microscopic hematuria and proteinuria during the acute attacks. Kidney biopsies from all patients revealed diffuse mesangial proliferative glomerulonephritis with intense IgM and C3 deposits; all were negative for amyloidosis. To our knowledge this is the first time the development of IgM nephropathy in patients with FMF is described.