Phenotypic variability of cardiovascularmanifestations in Marfan Syndrome. Possible role of hyperhomocysteinemia andC677T MTHFR gene polymorphism.

Aims The aim of this study was to evaluate (1) homocysteinemia and the prevalence of the C677T MTHFR potymorphism in Marfan patients and (2) whether the severity of cardiovascular manifestations is associated with homocysteinemia and/or C677T polymorphism. Methods and results We studied 107 patients subdivided into three subgroups based on the severity of cardiovascular manifestations: (A) no involvement (n=4); (B) mild involvement (n=45); (C) aortic dilatation or aortic dissection (n=58), and 189 controls. Total homocysteine (tHcy) was significantly higher in subgroup C than in subgroup B. In subgroup C patients with dissection tHcy was higher than in those without dissection. In subgroup C the prevalence of 677T homozygotes was higher, but not significantly, than in the subgroup B. In patients with dissection the prevalence of 677T homozygotes was significantly higher than in those without dissection and than in subgroup B. In the logistic regression analysis, severe cardiovascular manifestations and aortic dissection in Marfan patients were associated with tHcy plasma levels. Conclusions Our data indicate an association between the severity of the cardiovascular manifestations, in particular aortic dissection, and elevated tHcy levels. This suggests an important role for tHcy in determining phenotypic variability in Marfan patients and provides further evidence for the association of homocysteinemia with the damage of the vascular system.