Beyond their action on ED, PDE5 inhibitors are widely used in treatment of benign prostatic hypertrophy (BPH), Eisenmenger’s syndrome, Raynaud’s Disease, Intrauterine growth retardation (IUGR), Mountain sickness, Bladder pain syndrome/interstitial cystitis (BPS/IC), pulmonary arterial hypertension and type II diabetes (insulin resistance). The gene discussed is PDE5A; the disease is pulmonary arterial hypertension.