Abstract: FR-PO0918
Crescentic Membranous-Like Glomerulopathy with Masked IgG Kappa Deposits in an Adolescent
Session Information
- Pediatric Nephrology: Genetic Diseases, Development, Neonatal Nephrology, Glomerular Diseases, and More
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pediatric Nephrology
- 1800 Pediatric Nephrology
Authors
- Franco Linan, Mildred Carolina, Nicklaus Children's Hospital, Miami, Florida, United States
- Perez, Alexia M., Nicklaus Children's Hospital, Miami, Florida, United States
- Gomez Taborda, Stephanie, Nicklaus Children's Hospital, Miami, Florida, United States
- Alkhaldi, Saud Khalifa S, Nicklaus Children's Hospital, Miami, Florida, United States
- Kenan, Daniel J., Nicklaus Children's Hospital, Miami, Florida, United States
- Ramirez-Seijas, Felix, Nicklaus Children's Hospital, Miami, Florida, United States
Group or Team Name
- Nebroparty
Introduction
Membranous-like glomerulopathy with masked IgG kappa deposits (MGMID) is a rare glomerulopathy seen predominantly in young women and can be missed on routine frozen immunofluorescence, leading to misclassification.
Case Description
A 17-year-old female presented with edema, arthralgias, myalgias, fever, and abdominal/back pain. Initial evaluation suggested urinary tract infection, but persistentnephrotic-range proteinuria prompted nephrology workup. Urine protein-creatinine ratio was 4.5 g/g. Serologies were nonspecific, notable for positive ANA and Scl-70 withlow C4; lupus testing was negative. Kidney biopsy showed membranous-like glomerulopathy with masked IgG kappa deposits; 11 of 19 non-globally sclerotic glomeruli hadcellular to fibrocellular crescents, consistent with crescentic/rapidly progressive glomerulonephritis. Diagnosis required paraffin immunofluorescence with antigen retrieval tounmask IgG-kappa-restricted deposits. She was treated with corticosteroids, mycophenolate mofetil, hydroxychloroquine, and lisinopril. After 3 months, symptoms resolved and urine protein-creatinine ratio improved to 0.5 g/g.
Discussion
MGMID is uncommon and may mimic membranous nephropathy, lupus nephritis, or C3 glomerulopathy when routine immunofluorescence is unrevealing. Thiscase is notable for extensive crescent formation in an adolescent and early remission after combination immunosuppression. Teaching points are: (1) consider MGMID in young patients with proteinuria and autoimmune features despite negative routine immunofluorescence; (2) request paraffin immunofluorescence/pronase digestion whenmasked deposits are suspected; and (3) crescentic MGMID can present aggressively but may respond to prompt therapy.