Clinical Variability and Outcomes in C3 Glomerulopathy: A Single-Center Experience

Introduction: C3 glomerulopathy (C3G) is a rare disease with variable presentations ranging from asymptomatic isolated microscopic hematuria(21-36%), acute nephritis(16-38%), nephrotic range proteinuria(15-41%), frank nephrotic syndrome(12-55%) and AKI(8%). Unfortunately, once diagnosed with C3G, patients have a varied course with progression to ESKD (50% by 10 years) and need renal replacement therapy at a very young age. The treatment options include conservative management of proteinuria with RAAS blockade, and immunosuppressive therapy. Case Description: We present four cases of biopsy-proven C3G. Electron Microscopy was not done in all cases. Secondary causes of C3G had been excluded. Case 1 had a family history with membranoproliferative glomerulonephritis present in 2 generations and all siblings were affected with C3G. Case 2 had presented with AKI with crescents in kidney biopsy along with moderate Interstitial fibrosis and tubular atrophy. Case 3 was initially diagnosed and treated as a case of childhood onset nephrotic syndrome and biopsied in view of steroid resistance, which revealed a collapsing pattern with C3 deposits. Her nephrotic syndrome has been remitting and relapsing with response and proteinuria reduction to cnis but with relapses. Case 4 underwent partial remission and was offered a clinical trial with investigational drug Iptacopan, which showed evident benefit in proteinuria reduction and stabilization of eGFR. Discussion: The cases highlight the heterogeneity in presentation and progression of C3 glomerulopathy, ranging from isolated nephrotic syndrome to AKI with crescentic glomerulonephritis. Family history played a key role in Case 1, indicating a strong genetic predisposition. Case 2 progressed rapidly to ESKD despite immunosuppression, while Case 3 showed a relapsing-remitting course with steroid resistance. Case 4 showed partial remission following participation in a clinical trial, underscoring the potential role of emerging therapies in C3G management.