Genetic study of 21 Iranian patients affected with hemophilia B

Introduction: Hemophilia B is a recessively inherited X-linked bleeding disorder which results from deficiency of procoagulant factor IX (FIX). This disorder is caused by various defects in the factor IX gene, which is, being about 34 kb long and consisting of eight exons, localized in the Xq27 locus. Exon 8 is the largest exon of F9 gene and representing almost half of the F9 coding region. Approximately half of all F9 mutations are found in this exon.The birth prevalence of hemophilia B is approximately one in 30,000 live male births worldwide. To date, more than one thousand pathogenic mutations have been found in the F9 gene, most of them are missense mutations. Materials and Methods: Blood samples from 21 Iranian patients affected by F9 deficiency were collected and mutation analysis of all exons and their intron-flanking regions of F9 gene were performed using PCR and sequencing methods.Results: 21 mutations were identified in Factor IX gene including seven mutations in exon8, five mutations in exon2, two mutations in exon5, one mutation in exons 3, 4, 6 and 7, two mutations in promoter region and one mutation in intron4. The mutations found in this study included 10 missense mutations, 7 nonsense mutations and 1 deletion.Conclusion: In this study, as in previous studies, missense mutations were the most common type of mutations and most mutations were found in exon8. We found five novel mutations including, p.C97Y, p.N138T, p.G253EfsX11, p.S369V, and p.T381K in our patients.

Keywords:

F9 , gene , mutation , Hemophilia B , novel