Interestingly, only one SAPH patient (2.6%) was found to carry a variant in BMPR2, whereas mutations in BMPR2 are the most common genetic cause of disease in both heritable (~75% of patients) [11,12] and in those initially diagnosed as idiopathic (12–14% of the patients) PAH [10,11]. This evidence concerns the gene BMPR2 and pulmonary arterial hypertension.