AGTR1 and mitral valve disorder: In Marfan mice, multiple phenotypic manifestations, including aortic aneurysm, developmental lung emphysema, mitral valve disease, and skeletal muscle myopathy, correlate with enhanced transforming growth factor beta (TGFβ) signaling, while treatment with either TGFβ neutralizing antibody (NAb) or the angiotensin-II type 1 receptor (AT1R) blocker (ARB) losartan can ameliorate these phenotypes, in association with evidence of reduced TGFβ signaling (Neptune et al., 2003; Ng et al., 2004; Habashi et al., 2006; Cohn et al., 2007; Cook et al., 2015).