In Apoe−/− mice with an atherosclerotic producing diet, 5-LOX in the lamina adventitia rather than in the lamina intima contributed to the formation of aortic aneurysms associated with production of systemic inflammatory leukotrienes that indirectly affected extracellular matrix components including MMP-2 (Zhao et al., 2004). The gene discussed is ALOX5; the disease is aortic aneurysm.