Although there are 3077 known mutations in the FBN1 gene (UMD-FBN1 listed in the database: http://www.umd.be/FBN1/, updated on August 28, 2014) and more than 1500 different disease-causing FBN1 mutations, there is no single FBN1 genotype feature that qualifies as a reliable predictor of the clinical severity and long-term course of MFS. The gene discussed is FBN1; the disease is Marfan syndrome.