Group I (PAH) encompasses diverse etiologies, ranging from idiopathic origins and genetic mutations such as bone morphogenetic protein receptor 2 (BMPR2; the most common), AKL1, Endoglein, CVA1, SMAD9, and KCNK3 to drug-induced variants (including amphetamines, methamphetamines, cocaine, and fenfluramine-phentermine) and those interlinked with systemic conditions (such as connective tissue disorders, HIV infection, and congenital heart diseases) and PAH with features of venous/capillary involvement [6]. The gene discussed is SMAD9; the disease is pulmonary arterial hypertension.