FBN1 and Marfan syndrome: Several studies have been performed to investigate genotype–phenotype correlations, but few correlations between MFS clinical presentation and FBN1 mutation types were found [6]: nonsense mutations have been associated with more severe phenotype [7,8], missense mutations involving a cysteine have been associated with increased risk of ectopia lentis [9], and mutations within exons 24–32 to neonatal MFS and severe presentations in adults [10].