FBN1 and Marfan syndrome: Marfan syndrome (MFS) is a genetic autosomal dominant disorder of the connective tissue and is caused by mutations in the FBN1 gene, which encodes extracellular matrix protein fibrillin-1.141 Several studies have demonstrated that the transforming growth factor β (TGFβ) signalling system may also be involved in the development of MFS.142,143 MFS can manifest either at birth or as a progressive disease that can be found as late as 30–40 years old.