Hyperhomocyst(e)inemia and a Common Methylenetetrahydrofolate Reductase Mutation (Ala223 Val MTHFR) in Patients With Inherited Thrombophilic Coagulation Defects

• Published in: Arteriosclerosis, thrombosis, and vascular biology Vol. 17; no. 11; pp. 2924 - 2929
• Main Authors: Legnani, Cristina, Palareti, Gualtiero, Grauso, Francesca, Sassi, Simonetta, Grossi, Gabriele, Piazzi, Sandro, Bernardi, Francesco, Marchetti, Giovanna, Ferraresi, Paolo, Coccheri, Sergio
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.11.1997; Hagerstown, MD Lippincott
• Subjects: Adult; Aged; Antithrombin III; Antithrombin III Deficiency; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Disease Susceptibility; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Enzyme Activation; Factor V - genetics; Gene Frequency; Genotype; Homocysteine - blood; Homocystine - blood; Humans; Italy - epidemiology; Male; Medical sciences; Methylenetetrahydrofolate Reductase (NADPH2); Middle Aged; Oxidoreductases Acting on CH-NH Group Donors - genetics; Point Mutation; Protein C - metabolism; Protein S Deficiency - blood; Protein S Deficiency - genetics; Risk Factors; Thrombophilia - blood; Thrombophilia - genetics; Italy; Human; Methylenetetrahydrofolate reductase (NADPH); Enzyme; Cardiovascular disease; Hemopathy; Hereditary; Thrombosis; Venous disease; Vascular disease; Risk factor; Oxidoreductases; Mutation; Vein; Coagulopathy
• ISSN: 1079-5642; 1524-4636
• DOI: 10.1161/01.ATV.17.11.2924

To assess whether certain abnormalities of the sulfated amino acid metabolism are associated with the occurrence of thromboembolic events in patients with inherited thrombophilic conditions, the levels of homocyst(e)ine, before or after methionine load, and the presence of the Ala Val substitution in the 5,10-methylenetetrahydrofolate reductase (MTHFR) were evaluated in 119 subjects with a congenital single thrombophilic condition (type I deficiency of antithrombin n = 10, protein C n = 24, protein S n = 16; activated protein C resistance due to factor V Leiden mutation n = 69). Sixty-three subjects had experienced at least one documented thrombotic event, while the remaining 56 subjects were still free from any thrombotic symptom. Our results show that (1) high homocyst(e)ine levels, either in fasting condition or after methionine load, were not more frequent in subjects with inherited thrombophilic alterations (14.4%) than in normal control subjects (10% by definition) and (2) the frequency of hyperhomocyst(e)inemia was similar in thrombophilic subjects, who already have (14.3%) or have not (14.6%) experienced thrombotic events. As regards the MTHFR mutation, the homozygous condition was present in 23.2% of the thrombophilic patients versus 17.5% in the control subjects, a nonsignificant difference. The mutation was slightly more frequent in those thrombophilic subjects who had suffered a thrombotic episode (25.5%) versus those with no thrombosis (20.8%), with odds ratios of 1.61 (confidence interval (CI) = 0.58-4.52) and 1.24 (CI = 0.42-3.43), respectively. These differences were also non-significant. It is concluded that in subjects with inherited thrombophilias, a condition of hyperhomocyst(e)inemia "per se" is not a factor increasing the risk of thrombosis. The risk enhancement conferred by the MTHFR mutation, if any, seems to be slight or limited, and its significance could be ascertained only in a large multicenter trial. (Arterioscler Thromb Vasc Biol. 1997;17:2924-2929.)