PRDX4 and endothelial dysfunction: In the latter study, increased hypertension was also associated with increased methylation of Sod1, Txnrd2, and Prdx4. Other genes evaluated include Ace and Agt, with a trend towards lower methylation of a CpG island in the Ace TSS and upstream of the Agt TSS, in association with greater endothelial dysfunction [44] (Table 1).