Renin–angiotensin system (RAS) inhibitors control arterial hypertension, reduce proteinuria, and may treat erythrocytosis, but a meta-analysis of three randomized controlled clinical trials and two cohort studies, including 20.024 RTRs, showed no significant reduced risk of allograft loss or mortality in RTRs treated with RAS inhibitors [62]. This evidence concerns the gene REN and Hypertension.