This was actually an ongoing topic in the late '70's, that there was some speculation that there was a planet affecting the orbit of Pluto.


It will be interesting to see more information on it.

There's some debate about whether to classify it as a Kuiper belt object or not (and also whether Pluto should be reclassified a Kuiper belt object instead of a planet) since the main problem they have is that there is no current definition for what a planet is. Depending on how they lay out the wording Jupiter, Neptune, Saturn, and Uranus could end up as Brown Dwarf Stars and we'd lose Mercury and Pluto as planets due to their size.