CFHR1 and primary membranoproliferative glomerulonephritis: CFHR1,4: Complement factor H-related protein 1,4; PD: peritoneal dialysis; ESRD: end-stage renal disease; GI: gastrointestinal; aHUS: atypical hemolytic uremic syndrome; WTI: Wilms’ tumor gene 1; TMA: thrombotic microangiopathy; MPGN: Membranoproliferative glomerulonephritis; DMS: diffuse mesangial sclerosis; SNPs: single nucleotide polymorphisms