Abstract: TH-PO0529
Proteinuria Without Progression: Unmasking Monoclonal Glomerular Disease in a Patient with Known IgAN
Session Information
- Glomerular Diseases: IgAN, IgA Vasculitis, and More
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Amar Jeet Singh, Ishvinder Jeet Singh, MedStar Franklin Square Medical Center, Baltimore, Maryland, United States
- Al-Talib, Khalid K., MedStar Franklin Square Medical Center, Baltimore, Maryland, United States
Introduction
IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, while proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is a rare MGRS manifestation most frequently associated with IgG3κ restriction and often lacking a detectable systemic clone. Their sequential development is uncommon and diagnostically challenging.
Case Description
A 74-year-old Korean American woman with biopsy-proven focal IgAN, thin basement membrane disease, and CKD stage III–IV presented with progressive proteinuria despite stable serum creatinine and eGFR. Potential confounders, including suboptimal blood pressure control, calcium channel blocker use, and a simple renal cyst, were considered; however, unlikely to have contributed significantly. Given the discordance between rising proteinuria and preserved renal function, a repeat kidney biopsy was performed with histopathology revealing mesangial and endocapillary proliferative glomerulonephritis with IgG3κ monoclonal restriction on immunofluorescence, which was diagnostic of PGNMID, an entity that is distinct from the patient's prior biopsy. Comprehensive hematologic workup, including serum and urine immunofixation, serum free light chains, and bone marrow biopsy, was negative. The patient was then managed conservatively with optimized RAAS blockade, mineralocorticoid receptor antagonism, and SGLT2 inhibition, with preserved renal function at follow-up.
Discussion
In over 60% of cases, PGNMID lacks an identifiable circulating clone. This case highlights three key principles: worsening proteinuria in known IgAN should not be reflexively attributed to disease progression when eGFR remains stable; repeat biopsy is indispensable for identifying superimposed glomerulonephritis with distinct therapeutic implications; and the co-occurrence of IgAN and PGNMID suggests a shared immune dysregulation.
Repeat kidney biopsy was pivotal in diagnosing PGNMID superimposed on IgAN, even without detectable systemic gammopathy. Clinicians should maintain high suspicion for monoclonal glomerular disease when proteinuria worsens discordantly with preserved eGFR.