A mutation in factor I that is associated with atypical hemolytic uremic syndrome does not affect the function of factor I in complement regulation.
Factor I (FI) is the major complement inhibitor that degrades Ob and C4b in the presence of cofactors such as factor H (FH) and membrane cofactor protein (MCP). Recently, mutations and polymorphisms in complement regulator molecules FH and MCP but also in FI have been associated with atypical hemolytic uremic syndrome (aHUS). HUS is a disorder characterized by hemolytic anemia, thrombocytopenia an