Abstract: FR-PO0131
The "Thin" Line Between FSGS and Alport Disease: A Case Series
Session Information
- Hereditary Glomerular and Tubulointerstitial Kidney Diseases
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1202 Genetic Diseases of the Kidneys: Non-Cystic (Complex and Non-Cystic Monogenic)
Authors
- Moreno, Daniel Antonio, Rush University, Chicago, Illinois, United States
- Cimbaluk, David J., Rush University, Chicago, Illinois, United States
- Baxi, Pravir V., Rush University, Chicago, Illinois, United States
- Rodby, Roger A., Rush University, Chicago, Illinois, United States
Introduction
FSGS is a histologic pattern of injury on kidney biopsy which is attributed to primary or secondary causes, often without genetic evaluation. Thin basement membrane disease (TBMD) is a separate histologic finding often considered “benign”. We present 3 patients who had FSGS, one of which received immunosuppression (IS) and two of which also had TBMD. All 3 were found to have Alport disease on genetic testing, suggesting their hereditary nephritis may be responsible for the initial diagnosis of FSGS and thus was not necessarily benign.
Case Description
Patient #1 is a 21y man evaluated for progressive CKD. His urine showed 3.1g protein/24h and microscopic hematuria. Labs showed Cr 4.4 mg/dL, eGFR 19 mL/min. Kidney biopsy revealed FSGS, though the sample sent for EM had no glomeruli. Genetic testing later revealed pathogenic COL4A3 and COL4A4 mutations.
Patient #2 is a 55y man evaluated for 2.6 g/24h proteinuria. Labs showed Cr 1.4 mg/dL, eGFR 62 mL/min. His urine showed protein with no blood. Previous kidney biopsy was reported as FSGS. He was treated with a CNI. Two years later, he was referred for a second opinion where his biopsy was re-analyzed and identified FSGS with TBMD. Subsequent genetic testing revealed a pathogenic COL4A3 mutation.
Patient #3 is a 29y woman evaluated for 4.5 g/24h proteinuria and microscopic hematuria. Labs revealed Cr 0.73 mg/dL, eGFR >90 mL/min. Kidney biopsy revealed FSGS and TBMD. She was referred for genetic testing which revealed a pathogenic COL4A4 mutation.
Discussion
Genetic analysis has become an important tool in the evaluation of patients with nonspecific renal biopsy findings. We identified 3 patients with what appeared clinically to be secondary FSGS that were found to have Alport disease on genetic testing, essentially confirming the FSGS was likely secondary to this genetic condition. Our findings suggest this tool be used in all cases of secondary FSGS that lack an obvious etiology. This may establish a clearer diagnosis and avoid inappropriate IS.
Table 1: Clinical, biopsy, and genetic features of the three patients. MH: microscopic hematuria