IN-DEPTH REVIEWS

A Proposed Taxonomy for the Podocytopathies: A Reassessment of the Primary Nephrotic Diseases

Laura Barisoni ^*, H. William Schnaper ¹, and Jeffrey B. Kopp

*Department of Pathology, New York University School of Medicine, New York, New York; Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University School of Medicine, Chicago, Illinois; and Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland

¹ To whom correspondence should be addressed. E-mail: schnaper{at}northwestern.edu.

	Abstract

A spectrum of proteinuric glomerular diseases results from podocyte abnormalities. The understanding of these podocytopathies has greatly expanded in recent years, particularly with the discovery of more than a dozen genetic mutations that are associated with loss of podocyte functional integrity. It is apparent that classification of the podocytopathies on the basis of morphology alone is inadequate to capture fully the complexity of these disorders. Herein is proposed a taxonomy for the podocytopathies that classifies along two dimensions: Histopathology, including podocyte phenotype and glomerular morphology (minimal-change nephropathy, focal segmental glomerulosclerosis, diffuse mesangial sclerosis, and collapsing glomerulopathy), and etiology (idiopathic, genetic, and reactive forms). A more complete understanding of the similarities and differences among podocyte diseases will help the renal pathologist and the nephrologist communicate more effectively about the diagnosis; this in turn will help the nephrologist provide more accurate prognostic information and select the optimal therapy for these often problematic diseases. It is proposed that final diagnosis of the podocytopathies should result from close collaboration between renal pathologists and nephrologists and should whenever possible include three elements: Morphologic entity, etiologic form, and specific pathogenic mechanism or association.