Factor V (His 1299 Arg) in young Turkish patients with cerebral infarct.

Inherited gene defects related to the coagulation system have been reported as risk factors for stroke. Recently, a genetic component in the factor V (FV) gene that contributes to activated protein C resistance both in the presence and absence of FV 1691 G-->A was reported. This highly conserved FV gene haplotype was marked as R2 polymorphism, an A to G alteration at position 4070 in exon 13 that predicts the His 1299 Arg substitutions. The aim of this study was to evaluate the role of this mutation in Turkish children with ischemic infarct. The case-control study included 48 patients with cerebral infarction; all were 18 years of age or younger (range: 10 months to 18 years). Ten (20.8%) of the 48 patients were found to carry the FV 1299 His-->Arg mutation, one being homozygous. One patient who had a combination of FV 1691 G-->A and protein C deficiency also carried the FV 4070A mutation. A homozygous FV 1299A patient had a prothrombin (PT) 20210A mutation in the heterozygous state. The cerebral infarct risk for FV 1299 was found to be 2.4 (95% confidence interval 0.9-6.8) for all groups. When underlying conditions were excluded, the incidence of FV 1299 was found to be 8/35 (22.8%), but the risk was almost the same. When two other common thrombophilic mutations (i.e. FV 1691 G-->A and PT 20210 G-->A) were excluded, the incidence of FV 4070 mutation increased to 7/21 (33.3%). The risk also increased to 3.9 (95% confidence interval 1.2-12.3).