- The IBD international genetics consortium provides further evidence for linkage to IBD4 and shows gene-environment interaction. Pierik, M., Yang, H., Barmada, M.M., Cavanaugh, J.A., Annese, V., Brant, S.R., Cho, J.H., Duerr, R.H., Hugot, J.P., McGovern, D.P., Paavola-Sakki, P., Radford-Smith, G.L., Pavli, P., Silverberg, M.S., Schreiber, S., Taylor, K.D., Vlietinck, R. Inflamm. Bowel Dis. (2005)