the reality is that most mutations are disgusting and not like xmen (although mothing could surpass xmen in coolness and awesomeness). mutations is just another word for deformations
Mutations can manifest in any number of ways. A deformity is a mutation if it occurs in the womb, but a mutation is not a deformity.
I have a mutation but i'm not deformed, my three middle toes on each feet are as flexible as my three middle fingers just not as long, they aren't deformaties