Biopsy Proven Non-Amyloid Glomerular Diseases in Patients With Familial Mediterranean Fever

Abstract

AIM: Kidney involvement is the most serious organ involvement of Familial Mediterranean Fever (FMF), while the most common cause is AA type amyloidosis with serum amyloid AA deposition. However, vasculitis and other types of glomerulonephritis (GN) also have been reported. With this study we evaluated biopsy proven non-amyloid glomerular diseases in patients with FMF. Methods: At our Nephrology clinic, total 950 patients followed by diagnosis of FMF have been evaluated. Nine patients who had positive proteinuria ( >500 mg/day) but had negative amyloidosis in the tissue biopsy were made renal biopsy. Results: Nine patients underwent a renal biopsy, two patients were found to have IgA nephropathy (IGAN), three mesangioproliferative glomerulonephritis (MsPGN), three membranous glomerulonephritis (MGN) and one had immune complex glomerulonephritis. Two patients with IGAN and one patient with MGN with non-nephrotic proteinuria exhibited significant improvement with colchicine and angiotensin receptor blocker (ARB) therapy. Other patients were treated with colchicine, an ARB and immunosuppressive drugs. Upon evaluation for the FMF gene mutation, different mutations have been found for the same glomerulonephritis type. Conclusions: Other glomerular causes also must be investigated alongside amyloidosis in the case of kidney involvement in FMF patients. While patients with IGAN and other glomerulonephrities with non-nephrotic proteinuria can respond well to colchicine treatment, patients with more aggressive kidney involvement may require immunosuppressive therapy. Further studies are needed for revealing the relationship between FMF gene mutation and non-amyloid glomerular diseases.