It doesn't. Her only mutant power is her teleportation disks. This got the attention of a powerful demon, Belasco, and he targeted her. He opened a portal to limbo and lured her into it (she was like 6 or 8 years old at the time). Her friends and family tried to save her. One of them, I think Kitty, reached into the portal to pull her out. It worked but she was now a teenager.
Time passes differently in Limbo and Belasco had years to corrupt her in the split second time passed on Earth. The story is actually pretty awesome.