BMPR2 and idiopathic pulmonary arterial hypertension: Heterozygous germline mutations in the bone morphogenetic protein type 2 receptor (BMPR2; MIM #600799) have been identified in approximately 10 to 40 % of IPAH patients without a reported familial history of the disease and in over 80 % of patients with HPAH [4, 7–9].