In patients with end-stage renal disease (ESRD) receiving dialysis, elevated bloodpressure is common and poorly controlled in general.4 Although volume overload and sodium retention appear to be the mainpathogenic mechanism of hypertension in this population, other factors such asincreased arterial stiffness, activation of renin-angiotensin-aldosterone system,sleep apnea, activation of sympathetic nervous system, and use of recombinanterythropoietin may be also involved.5 This evidence concerns the gene REN and hypertensive disorder.