Immunoglobulin A Nephropathy (IgA Nephropathy) By Frank O'Brien, MD, Washington University in St Louis Reviewed / Revised Jun 2023 View Patient Education Symptoms and Signs Diagnosis Treatment Prognosis Key Points Topic Resources IgA Nephropathy (Mesangial... IgA Nephropathy (Mesangial... Immunoglobulin A (IgA) nephropathy is deposition of IgA immune complexes in glomeruli, manifesting as slowly progressive hematuria, proteinuria, and, often, renal insufficiency.