Abstract

 Background and Objectives

 Hemophilia 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 Methods

 Our 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.

 Results

 Two 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.

 Conclusions

 The 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.

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 Key words : Hemophilia B leyden, Factor IX, Promoter region�