Though there have always been debates about the drug to choose from ETA and ETB receptor selectivity for PAH treatment, presently ETA selective and dual ETA and ETB selective antagonists are in use, and ETA particular drugs showed more fluid retention compared to dual ETA and ETB receptors even in fibrosis-related disorders [18]. In conclusion, combination therapy is beneficial in achieving maximum efficacy, and although not curative, these drugs are helpful with tolerable SEs [18]. The gene discussed is EDNRB; the disease is pulmonary arterial hypertension.