Our results show that young adult male mice of 8- to 10-weeks old with the CD157 (BST1) null mutation display robust and well-replicated emotion-related behavioral phenotypes: CD157−/− mice displayed severe anxiety-related behaviors for the novel environment; CD157−/− mice also exhibited anxiety for non-social and/or social novel targets; Weak sociability with novel target mice and social avoidance for target males were also prominent phenotypes. The gene discussed is BST1; the disease is Anxiety.