FBN1 and Marfan syndrome: We can conclude that in the present study and previous studies, a decrease in fibrillin-1 has been reported in four conditions: patients with BAV without a fibrillin-1 mutation [8] (current study), patients with BAV and a fibrillin-1 mutation with [9] or without [31] clinical MFS features, and finally patients with clinically MFS and a fibrillin-1 mutation but no BAV [32].