Abstract: TH-PO0743
Drosophila Functional Validation of NEPTUNE-Identified Nephrotic Syndrome Variants
Session Information
- Glomerular Histopathology: Evolving Insights
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Lai Yee, Jennifer, University of Michigan, Ann Arbor, Michigan, United States
- Duan, Jianli, University of Maryland, College Park, Maryland, United States
- Zhao, Yunpo, University of Maryland, College Park, Maryland, United States
- Putnam, Nathaniel, University of Michigan, Ann Arbor, Michigan, United States
- Fermin, Damian, University of Michigan, Ann Arbor, Michigan, United States
- McNulty, Michelle, Boston Children's Hospital, Boston, Massachusetts, United States
- Onuchic-Whitford, Ana C., Brigham and Women's Hospital, Boston, Massachusetts, United States
- Wongboonsin, Janewit, Brigham and Women's Hospital, Boston, Massachusetts, United States
- Fishbein, Jennifer, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States
- Han, Zhe, University of Maryland, College Park, Maryland, United States
- Sampson, Matt G., Harvard Medical School, Boston, Massachusetts, United States
Background
Precision medicine aims to harness human genetics, particularly rare variants in disease-associated genes, to improve diagnosis and guide individualized therapy. However, despite the widespread use of whole-genome sequencing (WGS), interpreting the significance of rare missense variants remains a major challenge due to the scarcity of functional analysis. To address this gap, we employ a Drosophila model to assess the functional impact of selected putative pathogenic variants identified in NEPTUNE, a longitudinal nephrotic syndrome (NS) cohort.
Methods
70 genes implicated in monogenic NS and the two APOL1 risk alleles were analyzed in 620 patients from the NEPTUNE who had undergone WGS. A customized bioinformatics pipeline was used to identify putative pathogenic variants. Selected variants were further validated in Drosophila gene replacement models, comparing variant alleles to the human wild-type for rescue of nephrocyte defects caused by silencing homologous fly genes. General characteristics and clinical outcomes were compared among patients classified with Drosophila-validated monogenic NS and no known genetic form of NS.
Results
40 putative pathogenic variants were found in 36 patients (~6%), with 25 eligible for the study. 16 pathogenic and 2 predicted-benign variants were tested in Drosophila gene replacement models. 14 of 16 pathogenic variants (88%) failed to rescue nephrocyte defects, while both benign variants succeeded, indicating an 11% misclassification rate. Patients with putative monogenic NS had earlier onset than those without a genetic diagnosis (23 vs. 37 years, p=0.03). Those with validated variants and no APOL1 high-risk genotype had lower remission rates (20% vs. 65%, p=0.003), the trend of faster eGFR decline (-6.8 vs. -3.3 ml/min/1.73m2/yr, p=0.05), and were less likely to achieve first remission (HR 0.15, p=0.06).
Conclusion
Functional validation improves the accuracy of monogenic NS classification. Using gene knockouts and nephrocyte rescue, the Drosophila model effectively confirms putative pathogenic variants. In this North American NS cohort, patients with functionally validated monogenic NS had lower remission likelihood and faster kidney function decline, highlighting the value of precise genetic diagnosis.
Funding
- NIDDK Support