Board Thread:Theories and Speculation/@comment-28939725-20161201164545/@comment-30631705-20161207061943

Ravenlot 27 wrote: He was called a Senju descendand only once, when Madara mentioned that Nagato was quite suitable person for the Rinnegan transplantation due to his Senju lineage. Even if I just cannot recall when he was called a Senju again, it could still mean that Madara called him that way because of Uzumaki's relation with Senju. It's the most possible version.

Agreed, I always think about senju and uzumaki as one, through marriage, maybe.