FBN1 and stiff skin syndrome: Other degenerative disorders are caused by mutations in EGF-repeats encoded by other genes, including Marfan disease and Stiff Skin Syndrome (SSS), which are caused by mutations in FBN1. To determine whether LSL could be applied to these disorders, we cloned a sample of mutations in FBN1 into the LSL framework (LSL-FBN1) and compared activity parameters generated from disease-causing mutants to those of the corresponding wildtype sequence.