CFHR2 belongs to the complement factor H protein family. The human complement factor H protein family consists of the complement and immune regulators factor H, the factor H-like protein 1(FHL-1) and five factor H-related proteins (CFHR-1 to -5). Members of the H-related protein family are exclusively composed of individually folded protein domains, termed short consensus repeats (SCRs) or complement control modules. CFHR2 contains 4 Sushi (CCP/SCR) domains and is expressed by the liver and secreted in plasma. CFHR2 might be involved in complement regulation. It can associate with lipoproteins and may play a role in lipid metabolism.

CFHR1 is a secreted protein belonging to the complement factor H protein family.The human complement factor H protein family consists of the complement and immune regulators factor H, the factor H-like protein 1(FHL-1) and five factor H-related proteins (CFHR-1 to -5). Members of the H-related protein family are exclusively composed of individually folded protein domains, termed short consensus repeats (SCRs) or complement control modules. CFHR1 binds to Pseudomonas aeruginosa elongation factor Tuf together with plasminogen, which is proteolytically activated. CFHR1 might be involved in complement regulation. It can associate with lipoproteins and may play a role in lipid metabolism.

Complement factor H-related protein 5(FHR-5 for short), is a secreted protein which contains 9 Sushi (CCP/SCR) domains. It is expressed by the liver and secreted in plasma. The pattern of the deposits is similar to other complement components, suggesting that FHR-5 may play a role in complement activation and regulation. Defects in CFHR5 have been found in patients with atypical hemolytic uremic syndrome and may contribute to the disease. In contrast to typical hemolytic uremic syndrome, atypical forms have a poorer prognosis, with higher death rates and frequent progression to end-stage renal disease.