AGTR1 and Marfan syndrome: β blockers have been advocated to reduce the rate of aortic root dilatation in people with Marfan syndrome.3, 4 Experimental models of Marfan syndrome suggest that angiotensin-II type 1 receptor blockers (ARBs) can alter biological pathways, including excessive TGF-β signalling, that might contribute to the pathogenesis of aortic complications,5, 6, 7, 8 a finding that is supported by observational data in clinical studies.9