Carrier frequencies for thrombophilia-related genetic variants in a Romanian cohort

Genetic testing for hereditary thrombophilia, an inherited predisposition to thrombotic events, is increasingly available. To evaluate the rate of positive thrombophilia tests in our laboratory we analyzed the carrier status for common thrombophilia-related gene variants in a consecutive unselected cohort of 360 Romanian patients. Genetic tests were performed on a Real-Time PCR platform. Majority of patients (98.6%) carried at least one thrombophilic variant. The carrier frequencies for classical prothrombotic mutations in F5 (Factor V Leiden) and F2 genes (prothrombin G20210A mutation) were 11.67% (10.27% heterozygous, 1.4% homozygous) and 6.95% (6.39% heterozygous, 0.56% homozygous), respectively. Concurrently, high carrier frequencies for MTHFR c.677C>T, MTHFR c.1298A>C, and PAI-1 4G/5G variants, that are controversially associated with thrombophilia, were observed: 65.28% (52.5% heterozygous, 12.78% homozygous), 53.61% (45% heterozygous, 8.61% homozygous), and 78.61% (49.44% heterozygous, 29.17% homozygous), respectively. The impact of MTHFR genotypes on plasma homocysteine levels was also determined. Male carriers of TT homozygous genotype and CT heterozygous genotype of MTHFR C677T polymorphism had significantly higher levels of plasma homocysteine unrelated to age, compared to those harboring CC homozygous genotype (P=0.028). In unselected patients a high rate of positive thrombophilia tests was observed and the clinical implications of such results need to be carefully examined.