PROTHROMBIN G20210A MUTANT GENOTYPE IS A RISK FACTOR FOR CEREBROVASCULAR ISCHEMIC DISEASE IN YOUNG-PATIENTS

The factor II G20210A mutation is a recently identified congenital ris k factor for venous thrombosis. Its role in artery disease is still un defined, We investigated 72 patients (35 male and 37 female) with docu mented ischemic stroke occurred before 50 years of age and without ris k factors such as diabetes, hypertension, and hyperlipidemia; 198 thro mbosis-free individuals were investigated as the control group. We fou nd 7 heterozygotes (9.7%) and 2 homozygotes (2.7%) for the mutant fact or II allele among the patients and 5 heterozygotes (2.5%) among the c ontrols; the mutant factor II allele frequency in the patient group (7 .6%, 95% confidence interval [CI], 3.3 to 11.9) was significantly high er than in the controls(1.2%: 95% CI, 0.1 to 2.3; P = .0001). The prev alence of other investigated mutant alleles (factor V G1691A, methylen etetrahydrofolate reductase C677T) did not significantly differ betwee n the two groups. The odds ratio for ischemic stroke associated with t he carriership of the mutant factor II allele (both heterozygous and h omozygous genotypes) was 5.1 (95% CI, 1.6 to 16.3), Heterozygous genot ype was associated with a 3.8-fold increased risk for cerebral ischemi a (95% CI, 1.1 to 13.1); in particular, assuming an expected prevalenc e of homozygotes in the general population of 1.6 to 10,000 according to the Hardy-Weinberg equilibrium, the risk associated with the homozy gous genotype was estimated exceedingly high, being increased 208-fold . (C) 1998 by The American Society of Hematology.