We explored other variations of the complement system, including terminal pathway genes where deficiency of proteins has been associated with susceptibility to recurrent meningococcal disease [26–29] and two complement inhibitors to which N. meningitidis binds: CD46, which encodes membrane cofactor protein, a membrane-bound complement inhibitor [30,31] and C4 binding protein, which inhibits the classical pathway [32]. Here, CD46 is linked to meningococcal infection.