[Fibrillary nonamyloid glomerulonephritis: a rare etiology of nephrotic syndrome].

The fibrillary nonamyloïd glomerulonephritis is a glomerulopathy with fibrillar, nonamyloid deposits of predominantly polyclonal immunoglobulin G. It is an idiopathic glomerulopathy responsible for heavy proteinuria, generally in the nephrotic range, and renal failure up to end stage in 40 % of the cases after five years. The histologic pattern is variable, correlating with renal prognosis. The Congo red-negativity of the deposits and the size of the fibrils on electron microscopy make the differential diagnosis with amyloid deposits. There is no specific efficient therapy. Recurrence in the transplant is frequent, but with better renal prognosis.