Myocardial infarction in patients aged less than 40 years. Frequency of BclI polymorphism in the fibrinogen beta-chain gene and plasma fibrinogen.
BACKGROUND
Several polymorphisms in the genes encoding for three separate chains of fibrinogen have been described. Some of them (Hae III and B854) are associated with elevated fibrinogen plasma level.


OBJECTIVE
To determine the frequency of BclI polymorphism in the fibrinogen beta-chain gene (BclI betaFb) in young survivors of myocardial infraction (MI) and to assess the relationship between allele status, plasma fibrinogen concentration and the number of affected coronary arteries.


METHODS
The study group consisted of 99 male patients (mean age 43.5, range 29-49 years) with premature coronary artery disease (CAD) diagnosed by coronary angiography who had MI in the mean age of 37.4+/-3.2 years. The control group involved 78 age- and gender-matched healthy volunteers. DNA was extracted from peripheral blood leukocytes using standard methods. Fibrinogen blood concentration was determined using biuretic method. The BclI polymorphism in the fibrinogen beta-chain gene was investigated using polymerase chain reaction (PCR).


RESULTS
Obesity was found in 15%, smoking - in 89%, hypertension - in 21%, diabetes - in 14% and hyperlipidemia - in 86% of MI patients. A family history of MI was present in 50% of patients. Coronary angiography revealed single-vessel disease in 34%, two-vessel disease in 36%, and three-vessel disease in 16% of patients. In two patients coronary angiography was normal. The frequency of BclI polymorphism of the beta-fibrinogen gene was significantly higher in MI patients than in controls (40.4% vs 29.5%, p<0.01). Moreover, in MI patients carrying the mutant allele a higher concentration of blood fibrinogen was found in comparison to patients without this anomaly (3.87 vs 3.55 g/L, p=0.05). There was no evidence of an association between the number of affected coronary arteries and polymorphism of BclI betaFbg gene status. However, all patients carrying BclI polymorphism of betaFbg gene had abnormal coronary angiography, contrary to patients without any defect.


CONCLUSIONS
1. Polymorphism of BclI betaFbg gene is associated with an increased fibrinogen plasma level. 2. There is no association between BclI polymorphism of betaFbg gene and the number of affected coronary arteries. This may confirm the hypothesis of multi-factorial aetiology of CAD in young patients suffering MI.
Lewandowski
Krzysztof
K
Department of Haematology of University of Medical Sciences, Poznań, Poland.
Kwaśnikowski
Piotr
P
Elikowski
Waldemar
W
Zawilska
Krystyna
K
D000328:Adult; D016022:Case-Control Studies; D005340:Fibrinogen / Q000235:genetics* / Q000378:metabolism*; D019940:Genes, bcl-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
C115499:BBeta fibrinogen; D005340:Fibrinogen