Marfan syndrome (MFS) and congenital contractural arachnodactyly were the first diseases to be linked to the human FBN1 and FBN2 genes, respectively, which encode the fibrillin-1 and fibrillin-2 isoforms (Lee et al., 1991). The gene discussed is FBN1; the disease is congenital contractural arachnodactyly.