Factor V Leiden Is Associated with Premature Myocardial Infarction.
Authors: Peyvandi Flora , Spreafico Marta , Foco Luisa , Bernardinelli Luisa , Duga Stefano , Asselta Rosanna , Ardissino Diego , Kathiresan Sekar , Merlini Pierangelica , Mannucci Pier M. 
Published: April 2020

Abstract
Plasma levels of haemostatic proteins involved in coagulation and fibrinolysis may represent an important intermediate phenotype for cardiovascular diseases (because increased levels of these proteins have been associated with an increased/reduced risk of thrombosis). However, investigation in arterial diseases of gain-of-function polymorphisms of genes encoding coagulation factor V (F5 G1691A) and prothrombin (F2 G20210A), established risk factors for venous thrombosis, have generally indicated weak or no associations in a number of conflicting and inconclusive reports [Ye et al., Lancet2006;367:651–8]. These negative results might be due to the sample size, too small to reliably assess relatively small genetic effects. Recently, a meta-analysis of 4,944 patients and 7,090 controls on the association of the F2 G20210A and ischemic heart disease [Burzotta et al, Heart2004;90:82–6], and a meta-analysis of 66,155 cases and 91,307 controls on the association of haemostatic genetic variants and coronary artery disease (CAD) [Ye et al, Lancet2006;367:651–8], found that either F2 G20210A and F5 G1691A polymorphisms were associated with a moderately increased risk of CAD. Results from these meta-analyses, large but based respectively upon 19 and 100 different studies all of rather small size, should be taken cautiously. Considering that genetic factors play a particularly important role in CAD occurring in the young, with usually less coronary atherosclerosis and a high prevalence of normal or near-normal coronary angiograms, we chose to replicate the meta-analysis results by investigating an adequately large population of 1,864 Italian patients who developed myocardial infarction (MI) before the age of 45 yrs (1,655 men and 209 women) and 1,864 age- and sex-matched controls. Genotyping was performed by Sequenom MassARRAY platform. Statistical analysis was performed fitting a conditional logistic model with STATA 9.2 software. Our results showed that the minor A allele of F5 G1691A (2.6% frequency in cases and 1.7% in controls) was associated with a moderately increased risk of MI (OR:1.59; 95% CI:1.14–2.20; P=0.006). The association remained statistically significant after adjustment for traditional risk factors, including diabetes, smoking, hypertension, and hypercholesterolemia (OR:1.81; 95% CI:1.14–2.87; P=0.012). The minor A allele of F2 G20210A (2.4% frequency in cases and 1.9% in controls) was not associated with the risk of MI (OR:1.27; 95% CI:0.93–1.74; P=0.133), even after adjustment (OR:1.19; 95% CI:0.77–1.85; P=0.429). In conclusion, results of the previous meta-analyses are replicated only partially in this cohort of young MI patients, the largest investigated so far, as only the gain-of-function variant F5 G1691A (but not F2 G20210A) was associated with an increased risk of MI. Our results suggest that anticoagulant drugs might be considered for secondary prophylaxis of MI in patients with the F5 gene variant, who carry a procoagulant phenotype.