IIEF, International Index of Erectile Function; ED, erectile dysfunction; CKD, chronic kidney disease; ADAM, Androgen Deficiency in the Aging Male; HADS, Hospital Anxiety and Depression Scale; CAPD, continuous ambulatory peritoneal dialysis; PWV, pulse wave velocity; PDE5, phosphodiesterase type 5. The gene discussed is PDE5A; the disease is chronic kidney disease.