SMAD9 and pulmonary arterial hypertension: Nevertheless, also other genes were found to play a fundamental role in the initiation or progression of PAH in humans and rats: BMP9, CAV1, KV1.5, KCNK3, EIF2AK4, ENG, SMAD9, ALK1 (as reviewed in: Wang et al. 2016; Austin et al. 2012; Marsboom et al. 2017; Yuan et al. 1998; Remillard et al. 2007; Navas 2017; Eyries et al. 2014; Tu et al. 2019; Ramos et al. 2008; Jasmin et al. 2006; Lee et al. 2018).