title: The historical concept of interrelated conditions grouped together as a family of distinct diseases is not outdated: comment on the article by Baeten et al.
authors.forename: Henning
authors.initials: H
authors.lastname: Zeidler
mesh_terms: D000818:Animals; D006801:Humans; D013131:Spine / Q000473:pathology*; D025241:Spondylarthritis / Q000145:classification*