molecular characterization of the factor ix gene in 28 iranian hemophilia b patients

background: heterogeneous mutations in the human coagulation factor ix gene lead to an x-linked recessive bleeding disorder known as hemophilia b. the disease is distributed worldwide with no ethnic or geographical priority. materials and methods: the aim of this study was to characterize the factor ix gene mutations in 28 unrelated iranian hemophilia b patients. polymerase chain reaction (pcr) and direct sequencing was performed for all functionally important regions of the gene. haplotype analysis was performed using three markers. results: we identified 24 point mutations and four small deletions (one novel mutation). overall, 20 different mutations were found and patients with common mutations had identical haplotype. conclusion: these data confirm high molecular heterogeneity of the mutations causing hemophilia b and will enable carrier testing and prenatal diagnosis for family members.