Mutation detection in promoter region of coagulation factor IX in hemophilia B

Background and objectivesHemophilia B Leyden is an X chromosome-linked bleeding disorder characterized by an altered developmental expression of blood coagulation factor IX. This form of hemophilia has been found to be associated with a variety of single point mutations encompassing a 40-nucleotide region in factor IX promoter region. Mutations in factor IX gene promoter though relatively rare (about 2% of total) are important because they can give rise to the unique hemophilia B Leyden phenotype. Materials and MethodsOur objective was to study mutations in exon-1 in 4 3 Iranian hemophilia B patients to recognize possible cases of hemophilia B Leyden. Exon-1 of factor IX gene was amplified by PCR; then, conformational sensitive gel electrophoresis (CSGE) was used to distinguish cases having mutations in this region. ResultsTwo cases showed band shifts on CSGE. Exon-1 of the patients was directly sequenced. We found two different mutations in exon-1: the A/T mutation at +6 and the A/G mutation at +13. ConclusionsThe prevalence of hemophilia B leyden in B hemophilia patients (4.6%) in our results shows a higher frequency rate in Iran compared to that of other reported countries.