Clinical relevance of genotype–phenotype correlations beyond vascular events in a cohort study of 1500 Marfan syndrome patients with FBN1 pathogenic variants
Pauline Arnaud, Olivier Milleron, Nadine Hanna, Jacques Ropers, N Ould Ouali, Amel Affoune, Maud Langeois, Ludivine Eliahou, Florence Arnoult, P Renard, Marlène Michelon-Jouneaux, Marie Cotillon, Laurent Gouya, Cathérine Boileau, Guillaume Jondeau
Abstract
PURPOSE: Marfan syndrome (MFS) is a connective tissue disorder in which several systems are affected with great phenotypic variability. Although known to be associated with pathogenic variants in the FBN1 gene, few genotype-phenotype correlations have been found in proband studies only. METHODS: In 1,575 consecutive MFS probands and relatives from the most comprehensive database worldwide, we established survival curves and sought genotype-phenotype correlations. RESULTS: A risk chart could be established with clinical and genetic data. Premature termination codon variants were not only associated with a shorter life expectancy and a high lifelong risk of aortic event, but also with the highest risk of severe scoliosis and a lower risk for ectopia lentis (EL) surgery. In-frame variants could be subdivided according to their impact on the cysteine content of fibrillin-1 with a global higher severity for cysteine loss variants and the highest frequency of EL surgery for cysteine addition variants. CONCLUSION: This study shows that FBN1 genotype-phenotype correlations exist for both aortic and extra-aortic features. It can be used for optimal risk stratification of patients with a great importance for genetic counseling and personalized medicine. This also provides additional data for the overall understanding of the role of fibrillin-1 in various organs.