Crohn&;s disease is associated with

.10% of first degree relatives; 50% of monozygotic twins develop Crohn's disease. Genes NOD2 / CARD15 in chromosome 16q12 has got strong association with Crohn's disease. CARD15 is expressed in Paneth cells of the ileum. * Smoking is related to Crohn's disease as aetiology, as for relapse and for exacerbations. There is increased mucus membrane permeability - antigen induced cell mediated inflammatory response - release of cytokines like TNF, interleukin 2 -m defect in suppressor T cell - granuloma and other pathology. ref:SRB&;s manual of surgery ,ed 3,pg no 801