In this study, mice fed with a diet for 12 weeks to induce hyperhomocysteinemia showed increased Enhancer of Zeste Homolog 2 (EZH2) expression, which catalyzes the trimethylation of H3 at lysine 27, with its associated mark H3K27me3 along the cystic fibrosis transmembrane conductance regulator (CFTR) promoter in the mouse liver, resulting in a decrease in Cftr gene expression. The gene discussed is CFTR; the disease is hyperhomocysteinemia.