C3 Glomerulopathy: A Rare Entity with Future Directions

Abstract

C3 glomerulopathies are a rare group of glomerular diseases resulting from excessive activation of the alternative complement pathway. The pathogenesis involves genetic, acquired, or immunologic defects in regulators of the alternative complement pathway. Currently, these diseases have a chronic course with progression to end-stage renal disease in up to 50% of adult patients. We report a case of a young woman who presented with nephrotic syndrome and renal disfunction. During follow-up, the diagnosis of C3 glomerulopathy associated with complement factor I deficiency was established. After relapse of nephrotic proteinuria, immunosuppressive therapy with mycophenolate mofetil and glucocorticoid was added to supportive care. There is no disease-specific therapy for C3 glomerulopathies, and treatment is focused on reducing proteinuria and renal inflammation. Supportive treatment with ACE inhibitors or angiotensin receptor blockers is the first-line therapy. Immunosuppressive therapy with mycophenolate mofetil plus corticosteroids is associated with higher chances of clinical remission and lower risk of kidney failure. Complement targeting therapies, such as eculizumab, avacopan, danicopan, iptacopan, and pegcetacoplan, are being studied as potential new therapeutic options. This article highlights the need for more clinical trials to test new therapeutic agents, as well as to better understand the heterogeneity of the disease and its long-term outcomes.

Keywords

• complement c3
• glomerulonephritis/therapy