As an exercise‐induced myokine, irisin represents a potentially valuable therapeutic target not only for its anti‐oxidative or anti‐inflammatory functions, but also for its beneficial effects in a variety of chronic diseases such as kidney disease, diabetes, hypertension and others.[1, 22, 23, 24] However, the role of irisin in PAH has not been defined. The gene discussed is FNDC5; the disease is pulmonary arterial hypertension.