Abstract: TH-PO0541
Proteinuria in Diagnostic Limbo: Unraveling an Atypical Cause of Proteinuria
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
Author
- Bustos, Brian, Bustos Medical Group, Washington, District of Columbia, United States
Introduction
Proteinuria in SLE is frequently attributed to lupus nephritis; however, alternative forms of podocyte injury may mimic or coexist with lupus-related kidney disease. Lupus podocytopathy is a rare entity characterized by nephrotic-range proteinuria and diffuse podocyte foot process effacement without significant immune complex deposition. Similarly, APOL1-associated nephropathy may present with overlapping clinical and histopathologic findings, creating diagnostic and therapeutic uncertainty. We present a diagnostically challenging case of severe proteinuria at the intersection of autoimmune and genetic-mediated podocytopathy.
Case Description
A 49 year old African American female with HTN and SLE was referred from her rheumatologist for AKI with creatinine of 3.78 where her baseline creatinine was 0.9-1.0. She denied nausea, vomiting, or diarrhea and reports no NSAID use or new medications. Urinalysis showed protein +3, WBC 0-5, RBC 0-2. Urine total protein was 9,145 mg/g. Immunologic evaluation was negative. Renal biopsy showed three glomeruli with segmental sclerosis with podocyte capping, and focal features of a tip lesion. Tubular atrophy and interstitial fibrosis involved approximately 10% of the cortical sample. There was no evidence of immune complex deposition by IF and EM. EM showed moderate to severe podocyte foot process effacement. She was initially managed with losartan and farxiga, though repeat urine total protein was 10,900 mg/g. Genetic testing was positive for homozygous APOL1-Mediated Kidney Disease with variant c.[1024A>G;1152T>G] (p.[Ser342Gly;Ile384Met]) (G1 allele). Due to concern for component of lupus podocytopathy, she was initiated on rituximab infusions as she has not tolerated steroids in the past. Repeat urine total protein was 4819 mg/g, with microalbuminuria of 3335 mg/g after 6 months of therapy.
Discussion
This case highlights the complexity of evaluating nephrotic-range proteinuria in patients with concurrent autoimmune and genetic risk factors for kidney disease. Given the overlapping presentations yet differing prognostic and therapeutic implications of these entities, accurate diagnosis remains critical. This case emphasizes the importance of integrating serologic, histopathologic, and genetic data when assessing atypical proteinuria and contributes to the growing recognition of overlapping podocytopathies in complex kidney disease.