In some superhero campaigns the world can be a more dangerous place depending on how you attained your super powers. Having been born with a "mutant ability" your character is in danger on a regular basis. Certain authorities hunt this character down and can detect the character's location using advanced technology keyed to "mutant radiation signatures." Your hero also has a harder time convincing the regular people that he is a hero and not a menace to society.
Mutants are "wanted" by certain authorities and will be arrested and "studied" if captured by one of these organizations. The character should have infrequent encounters with agents of these authorities. In addition, when dealing with non-mutants your character suffers a -2 Charisma penalty.
Though this Hinderance is essentially a combination of the Wanted (Minor) and Outsider (Minor) hinderances, it seems natural that this should be a single hinderance in a supers campaign. Keep in mind that in addition to the mutants inhabiting the Marvel universe, there are characters like the Shroud who would merely have the Outsider hinderance. There are also some mutants who are more mistrusted than others.