Abstract: SA-PO263

Describing the Natural History of C3 Glomerulopathy

Session Information

Category: Glomerular

  • 1005 Clinical Glomerular Disorders

Authors

  • Gumpert, Chloe E, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
  • Smith, Richard J., Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, Iowa, United States
  • Nester, Carla M., Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, Iowa, United States
Background

C3 glomerulopathy (C3G) is a rare, aggressive form of complement-mediated glomerular disease that carries the highest risk for irreversible renal failure of the known glomerular diseases. This dismal outlook results not only from a poor understanding of the natural history of disease (i.e. both what marks disease activity and what constitutes treatable disease), but also from the lack of disease-directed therapeutics. We have recently expanded the clinical data capture for our research subjects, and now include all patients with C3G seen in the University of Iowa’s Rare Renal Disease Clinic. The following is the initial clinical cohort.

Methods

Data are derived from the clinic records of a contemporary cohort of 36 patients with a biopsy-proven diagnosis of C3G who have at least 1 year of clinical follow-up. Data are reported (without censoring for broader pathology characteristics) from time of presentation and at last follow-up.

Results

29 C3GN and 7 DDD patients met criteria for evaluation. There was no difference in C3 at presentation or follow-up between the two disease types. No statistically significant difference was noted in eGFR at presentation. At last follow-up, 38% and 57% of C3GN and DDD patients respectively were at CKD Stage 3 or greater. DDD patients were more likely to progress to transplant.

Conclusion

C3GN and DDD are clinically similar, aggressive diseases with high risk for progression to late stage CKD. Routine clinical parameters and biomarkers of disease do not distinguish the two groups. Expansion of the cohort size and longitudinal re-evaluation is ongoing. Analyses of pathology and expanded biomarkers are ongoing. We expect this data will be critical for devising effective treatments for this group of patients.

Table 1. Clinical and biological data according to histological type
At Time of Disease Onset
 C3GN (n=29)DDD (n=7)p value (α=0.05)
Serum Cr (mg/dL)1.51.60.80
eGFR (mL/min/1.73m^2)54.352.00.76
Serum C3 (mg/dL)50.366.70.62
At Time of Last Follow-Up
Mean Follow-Up (yrs)4.63.80.97
Serum Cr (mg/dL)2.73.70.61
eGFR (mL/min/1.73m^2)53.446.50.91
≥ Stage 3 CKD11 (38%)4 (57%)0.48
Serum C3 (mg/dL)75.979.60.92
% Transplant10.742.90.04
% Transplant Recurrence014.30.04

Funding

  • NIDDK Support