BMPR2 and pulmonary arterial hypertension: Since lung biopsies are contraindicated in PAH patients due to a high risk of morbidity and mortality [1], our objective was, firstly, to clarify whether BMPR2 mRNA and protein blood expression levels showed differences in affected BMPR2 variant carriers in comparison to non-variant carriers and to healthy controls; and secondly, we aimed to correlate BMPR2 mRNA and protein blood expression levels with clinical and laboratory parameters.