BMAL1 and colitis: Global knockout of circadian genes is not sufficient to characterize clock function in specific tissues as interference may come from other tissues, which may explain why different colitis phenotypes are observed in global knockout and intestinal epithelial-specific knockout of Bmal1. Global Bmal1-deficient mice also exhibit age-associated dilated cardiomyopathy, with dysfunction of left ventricular dilatation and contraction (Lefta et al, 2012).