BMPR2 and heritable pulmonary arterial hypertension: The most relevant gene mutation by far involves the BMPR2 gene, which is affected by loss of function mutations in 70–80% of the HPAH and in 10–20% of the IPAH patients.72 Additionally, mutations in genes not part of the canonical TGFβ signalling cascade have also been reported (i.e. CAV1,73TBX4,74EIF2AK4,75 and KCKN376).