This gene is a member of a small complement factor H (CFH) gene cluster on chromosome 1. Each member of this gene family contains multiple short consensus repeats (SCRs) typical of regulators of complement activation. The protein encoded by this gene has nine SCRs with the first two repeats having heparin binding properties, a region within repeats 5-7 having heparin binding and C reactive protein binding properties, and the C-terminal repeats being similar to a complement component 3 b (C3b) binding domain. This protein co-localizes with C3, binds C3b in a dose-dependent manner, and is recruited to tissues damaged by C-reactive protein. Allelic variations in this gene have been associated, but not causally linked, with two different forms of kidney disease: membranoproliferative glomerulonephritis type II (MPGNII) and hemolytic uraemic syndrome (HUS).