A study looking at 144 different BMPR2 mutations from a broad international PAH patient cohort, predicted that around 70% of all the mutations result in non-mediated decay of the truncated transcripts.80 Follow-up studies concluded similar findings.77 The resulting haploinsufficiency is therefore the main cause of disrupted TGFβ signalling. Here, TGFB1 is linked to pulmonary arterial hypertension.