As an example, the expression of bone morphogenetic protein receptor 2 (BMPR2) is highly associated with heritable PAH and is often present in IPAH (Rubin, 2017), but this mutation has not been found in SSc-PAH patients, at least in two small genetic studies (Morse et al., 2002). The gene discussed is BMPR2; the disease is pulmonary arterial hypertension.