FBN1 and Marfan syndrome: Although CCA and MFS are often difficult to differentiate clinically because of their phenotypic similarities, CCA can be distinguished from MFS genetically: the fibrillin-1 (FBN1) gene defects on 15q15-21.3 may cause MFS, while the fibrillin-2 (FBN2) gene on 5q23-31 is linked to CCA [1,7].