Diagnosis and classification of IgA nephropathy.

IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide. The diagnostic hallmark of IgAN is the predominance of IgA deposits in the glomerular mesangium. The natural history of IgAN is variable. Clinical features including heavy proteinuria, elevated serum creatinine level, hypertension at presentation, and advanced histologic findings can strongly predict the risk of progressive chronic kidney disease. This article reviews the evolving history of diagnostic criteria of IgAN and the controversial aspects of the Oxford Classification. To date, there is no disease-targeted treatment for IgAN. Advances in understanding of the pathogenesis may help with earlier diagnosis and better monitoring of the treatment response and clinical course, and in the development of targeted therapy in the future.