THE INVENTION RELATES TO ENGINEERED POLYPEPTIDES COMPRISING FC VARIANTS AND THEIR USES. MORE SPECIFICALLY, FC VARIANTS ARE DESCRIBED EXHIBITING REDUCED EFFECTOR FUNCTION. THESE VARIANTS CAUSE A BENEFIT FOR A PATIENT SUFFERING FROM A DISEASE WHICH COULD BE TREATED WITH AN ANTIBODY FOR WHICH IT IS DESIRABLE TO REDUCE THE EFFECTOR FUNCTION ELICITED BY ANTIBODIES. FIGURE 1.