CLDN18 and Osteopenia: As Cldn‐18 was globally disrupted and Cldn‐18 is expressed in other tissues, the purpose of this study was to investigate the possibility that the osteopenia phenotype of Cldn‐18 KO mice is mediated in part by disruption of Cldn‐18 in other tissues, that is, the stomach (Krause et al. 2008; Tureci et al. 2011).