Even if one argues that the dominant feature causing colitis in Winnie and Eeyore is the depletion of the mucus barrier, then these two spontaneously occurring models demonstrate how mucin depletion sufficient to initiate colitis can occur via simple missense mutations in Muc2, and that heterozygosity for such mutations is sufficient to cause enhanced susceptibility to environmental insults. Here, MUC2 is linked to colitis.