The search for genotype/phenotype correlation in Marfan syndrome: to be or not to be?

This editorial refers to ‘Genotype impacts survival in Marfan syndrome’, by R. Franken et al . [doi:10.1093/eurheartj/ehv739][1] Marfan syndrome (MFS) is an autosomal dominant inherited connective tissue disorder with the main manifestations in the skeletal (overgrowth), ocular (ectopia lentis), and cardiovascular system. The latter include predominantly mitral valve disease (prolapse with or without insufficiency) and aortic aneurysm most prominently at the level of the sinuses of Valvalva. The disease has an estimated prevalence between 1/3000 and 1/5000, irrespective of gender or ethnicity. The large majority of MFS patients will ultimately develop aortic aneurysm and, if undetected, be prone to aortic dissection, most commonly type A dissections starting from the dilated aortic root, but type B dissection have also been described. Since its initial description in 1898 by Antoine-Bernard Marfan, it took ∼100 years to discover the genetic basis of the condition. Dietz and colleagues demonstrated that mutations in the FBN1 gene, coding for the extracellular matrix protein fibrillin-1, are causal of the disease.1 Over the past 25 years, >3000 different FBN1 mutations have been described. With the advance of genetic technology, mutation detection is now feasible in >90–95% of MFS patients, and molecular testing has become an integral part of the diagnostic decision-making process. According to the revised Ghent Marfan nosology, a clinical diagnosis can be made if one of the four following rules in an index patient is fulfilled: (i) the presence of ectopia lentis and aortic root dilatation; (ii) aortic root dilatation and FBN1 mutation; (3) aortic root dilatation and systemic score; and (iv) ectopia lentis and FBN1 mutation.2 Although genetic analysis of FBN1 now contributes significantly to the diagnostic process, its … [1]: http://dx.doi.org/10.1093/eurheartj/ehv739