Factor H is a control protein in the complements system. Autoantibodies against Factor H can trigger an atypical hemolytic uremic syndrome (HUS).

Synonym: deficiency of CFHR (complement Factor H related) plasma proteins, Factor H autoantibody positive, hemolytic uremic syndrome (DEAP-HUS)



(1) homozygous deletion of CFHR1 and CFHR3 genes

(2) autoantibodies against Factor H

(3) hemolytic uremic syndrome with renal failure

(4) decreased serum C3 concentrations

(5) decrease Factor H activity in plasma with normal antigenic levels

(6) no evidence of Shiga toxin


The autoantibodies interfere with Factor H surface binding functions, which results in defective regulation of the alternative pathway. Activation of the alternate pathway results in endothelial damage.

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