FBN1 and Marfan syndrome: Interestingly, a 2-fold increase in MFAP4 abundance in the ascending aorta of patients with MFS has been previously reported using difference in-gel electrophoresis.46 The coordinated expression with FBN1 may be expected, given that MFAP4 has been demonstrated to bind and colocalize with FBN1 to aid in elastin fiber formation.45 However, correction of the FBN1 mutation in iPSC-derived vascular SMCs had no direct effect on MFAP4 levels, as these SMCs produced little elastin in culture.