CBS and myocardial infarction: Inconsistent with the observed elevation of methionine, circulating transcriptomics of MI patients (GSE48060) showed that among the methionine abundance-related genes, methionine synthase 5-Methyltetrahydrofolate-Homocysteine Methyltransferase (MTR) expression decreased and Cystathionine β-synthase (CBS, converting homocysteine to cystathionine) increased (p < 0.05, Figure 4B).