Board Thread:Naruto Discussions/@comment-25113423-20150207211028/@comment-1512913-20150217131258

Kimimaro had both Shikotsumyaku and Cursed Seal (Senjutsu) and no horns, so I doubt there's a relation. Horns are simply something that Kaguya and her sons had. EDIT: The Shinigami also has horns.