Abstract: TH-PO0533
A Rare Case of IgAN in a 20-Year-Old Patient with Negative DNAJB9 and Congo Red Fibrillary Deposits
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
- Benjamin, Shijo, Brown University, Providence, Rhode Island, United States
- Dailey, Jennifer, Brown University, Providence, Rhode Island, United States
- Tang, Jie, Brown University, Providence, Rhode Island, United States
Introduction
We present a unique case of IgA nephropathy (IgAN) with fibrillary mesangial deposits and significant chronic features in a young healthy college student.
Case Description
A 20-year-old female college student with no past medical history presented with new onset gross hematuria and proteinuria per urinalysis. Two months ago, she noticed gross hematuria lasting for 10 days in association with a sore throat. She was empirically treated for a UTI with subsequent resolution of hematuria. About one week ago, she had a recurrence of gross hematuria unrelated to menstruation. Her roommate had infectious mononucleosis and Strep throat at the time. Her renal function was normal but ASO titer was elevated at 345 IU/mL. Urine sediment revealed 20+ RBCs per HPF with >20% showing dysmorphic features. Urine protein to creatinine ratio was 3.24 g/g. Renal biopsy showed findings consistent with IgAN (M1E0S1T0C1), including 14% segmental glomerulosclerosis, 21% fibrocellular crescents, 43% fibrous crescents, and mild IFTA (~25%). Immunofluorescence showed granular mesangial staining for IgA (3-4+), C3 (3+), IgG (1+), IgM (trace), kappa/lambda (1+), and negative C1q. EM showed mesangial fibrillary deposits (9-20nm) that were Congo red negative, and DNAJB9 negative by both immunohistochemistry and tissue microdissection/mass spectrometry. Figure below depicts (A) Focal area of IFTA, (B) Fibrocellular crescent, (C) IgA granular mesangial staining, (D) Mesangial fibrillary material. The patient was initially started on losartan, which was later replaced with Sparsentan and Nefecon. Her urine sediment showed significant improvement with proteinuria reduced to 0.4 g/g 3 months later.
Discussion
This represents the first reported case of IgAN with DNAJB9-negative fibrillary polytypic mesangial deposits and advanced chronic pathologic features in an otherwise healthy young lady. The long-term prognosis associated with these atypical findings remains uncertain.