Mutation of the 5,10-C677TMethylenetetrahydrofolateReductase Gene in Young Patients with Venous Thromboembolism

Overview

Mild hyperhomocysteinemia has been shown to be a risk factor for venous thrombosis and may becaused by genetic and/or environmental factors. The most common genetic variant that can result inmild hyperhomocysteinemia is caused by thermolabile variant of the enzyme C677T methylenetetrahydrofolatereductase (MTHFR). The frequency of the homozygous variant of MTHFR genotype wasobserved in range 10 to 15 % and the heterozygosity for variant is more frequent in these subjects inabout 45% of the European population. The prevalence of a mutation in the MTHFR gene is slightlyhigher in patients with venous thromboembolism. The frequency of MTHFR was assessed in a group of115 consecutive patients (from 115 unrelated families) with first or recurrent episode of venousthrombosis under the age of 50. The authors confirmed high prevalence (heterozygotes constituted41.7% and homozygous 11.4%) of this mutation in young thrombophilic patients in accordance withsimilar cohorts. MTHFR variant is not a risk factor for thrombosis itself. The authors continue thisstudy by measurement of fasting homocysteine and acid folic levels, with the aim of identification ofsubgroup patients with MTHFR mutation who have the risk of venous thromboembolism.Key words: venous thromboembolism, mild hyperhomocysteinemia, thermolabile variant of the C677Tmethylenetetrahydrofolate reductase, young patients

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