Fbn-1 and -2 are both found to be expressed in the cancellous bone.229 In humans, mutations in FBN-1 and FBN-2 cause pleiotropic manifestations in Marfan syndrome (MIM #154700) and congenital contractural arachnodactyly (MIM #121050), respectively77,230 (Table 2). This evidence concerns the gene FBN1 and Marfan syndrome.