CFHR1 and hemolytic-uremic syndrome: It is also interesting that the frequencies of the aHUS-risk variants CFHR3*B and CFHR1*B in our SP-HUS cohort (0.346 and 0.615, respectively) are higher than in control individuals (0.242 and 0.368), and comparable to the frequencies observed in the aHUS (0.355 and 0.467) and P-aHUS (0.462 and 0.455) cohorts.