The occurrence of ankylosis and severe subclinical gut inflammation with increasing serum Lcn2 levels implicates a possible synergistic contribution of gut and bone to circulating Lcn2 levels since neither gut inflammation alone in C3FeB6-A/Aw-jwt/wt mice nor ankylosis alone in ank/ank mutants was reflected in increased serum levels of Lcn2. This evidence concerns the gene LCN2 and ankylosis.