Evidence for a role of H2S in the pathogenesis of hypertension is suggested by the observation that plasma H2S concentrations are lower in patients with grade 2 or grade 3 hypertension, portal hypertension, and pulmonary hypertension90–92 and in preeclampsia where plasma H2S levels and placental CBS mRNA expression are decreased93,94. The gene discussed is CBS; the disease is Hypertension.