C3 glomerulopathy-3 (C3G3) is an autosomal dominant kidney disease characterized by the onset of microscopic or macroscopic hematuria in the first 3 decades of life, followed by variable progression of renal disease. After age 30, about half of patients continue to have episodic hematuria while maintaining normal renal function, whereas the other half develop proteinuria and progressive renal failure or end-stage renal disease. In some cases, renal dysfunction may be triggered or exacerbated by an infectious disease, often an upper respiratory infection or pharyngitis. Some patients may also develop hypertension. Renal biopsy shows glomerular C3 deposition and mesangial proliferation with glomerulonephritis. Membranoproliferative glomerulonephritis (MPGN) may also be observed on renal biopsy. Males tend to have a more severe phenotype than females and are more likely to develop end-stage renal disease, often necessitating dialysis or renal transplant (summary by Athanasiou et al., 2011). For a general description and discussion of genetic heterogeneity of C3G, see C3G1 (609814).