Scientific Journal of

  Abstract

 Background and Objectives

 Hemophilia B is an inherited recessive X-linked bleeding disorder caused by deficiency or defect of procoagulant factor IX (FIX). The factor IX gene spans 35kb of DNA and comprises of 8 exons. Mutations in the factor IX gene may result in deficient or defective coagulation factor IX causing the bleeding tendency known as hemophilia B. The aim of this study was to identify the causative mutations and genotype-phenotype correlation for mutations in some known patients with hemophilia B in Isfahan province.

 Materials and Methods

 After informed consent was obtained, genomic DNAs of 24 hemophilia B patients referred to Omid hospital were extracted according to standard protocols. PCR amplification and single strand conformation polymorphism (SSCP) on nondenaturing polyacrylamid gel were performed separately on each sample for eight exons and exon-intron boundaries and promoter. The results of SSCP were compared to normal control and sequencing was performed for those with different migration patterns.

 Results

 The sequencing results showed 70.8% missense mutation, 16.7% deletion, 8.3% nonsense mutation, and 4.2% insertion. Many of the mutations had occurred in exon 8 it came out to be similar to haemophilia B mutation database. Malmo polymorphism (Ala 148 Thr) was found in one family. Four novel mutations not previously reported in the database were also found.

 Conclusions

 This study confirms the marked heterogeneity of factor IX mutations in the population. The results could be used to develop a national database and offer genetic counselling to families.

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 Key words : Hemophilia B, SSCP, Mutation�