In some of Warren Ellis' work on Astonishing X-Men, issues #25-30 ("Ghost Box"), some nefarious individuals from other Earths use a Ghost Box to cross over to Earth-616, finding it relatively undefended given the tiny number of mutants post-House of M. They (the people of "The Annex") are looking to conquer Earth-616 for themselves, and have sent mutant scouts.
This particular dimension (and, it is implied, others) do have mutants, though there is some mentioned that their X-gene is present on a different chromosome. Beast and others theorize that in the instant that Hope was born, many dimensions would have sprung into being in the multiverse in which mutants were common again.
Apparently the Scarlet Witch affected the entire multiverse during House of M. However, how is it that Hope's birth is able to do the same thing somehow, creating parallel dimensions? Is there something significant to the entire multiverse about Hope's birth?