The over-expression studies described above did not test the possibility that NOD2 bearing a Blau mutation may exert a dominant-negative effect on the function of co-existing intact NOD2 because the severity of TNBS-colitis induced in the C57BL/10 mice under study was too severe to permit evaluation of greater severity in mice over-expressing Blau-NOD2. The gene discussed is NOD2; the disease is colitis.