There is increasing evidence that cellular senescence may be contributory to the development of type 1 (idiopathic) PAH, with increased expression of p21, p16, and the DNA damage markers γH2AX and 53BP1 in pulmonary endothelial and vascular smooth muscle cells (Kyi et al, 2022; Born et al, 2023). The gene discussed is CDKN2A; the disease is pulmonary arterial hypertension.