In SSc-ILD, anti–angiotensin II type 1 receptor and anti–endothelin-1 type A receptor antibodies, together with activation of the renin–angiotensin and endothelin systems, promote fibrosis progression, vasoconstriction, and vascular injury—mechanisms underlying the increase in endothelin-1 [3]. The gene discussed is EDN1; the disease is interstitial lung disease.