FBN1 and Marfan syndrome: The clinical features of DA9 overlap with Marfan syndrome which is attributed to mutations in fibrillin-1, FBN1. In a comparison between Marfan syndrome and DA9, one researcher reported that the abnormally shaped auricular helices were the trademark of CCA and, hence, absent in individuals with Marfan syndrome (Godfrey et al., 1995).