Among these, only 3 patients (1 with IC-MPGN and 2 with C3G) were found to carry mutations in complement genes, more precisely presenting as heterozygotes for mutations in factor H-related protein (CFHR)1, heterozygotes for CFHR3, and deletions in the CFHR1 and CFHR3 genes. This evidence concerns the gene CFHR3 and primary membranoproliferative glomerulonephritis.