To further delineate the roles of Smad and ERK signalling in directing SMC gene expression, primary aortic root SMC lines derived from MFS patients (n = 5) were treated with either (a) TGF‐β inhibitor (SB431542, 10 μmol/L), (b) TGF‐β (10 ng/mL) or (c) TGF‐β with ERK inhibitor (PD98059, 20 μmol/L) and compared to control media. Here, TGFB1 is linked to Marfan syndrome.