– 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.