NOD2 and Cowden disease: NOD2 has been proposed as a relevant protective molecule against the invasiveness of certain bacteria including L. monocytogenes or H. hepaticus; NOD2 deficient mice lack an adequate production of cryptins including defensins [182] which are a critical regulatory mechanism in the epithelial microbial interface; however a reduction in defensins has been reported in CD patients without NOD2 mutations [183].