Molecular analysis of factor IX gene in an Iranian female with severe hemophilia B

Hemophilia B, a recessive X-linked coagulopathy, is rare in females, and only a few cases have been reported so far. In this report, we describe a 9-year-old female, offspring of a consanguineous marriage, with a clinically severe course of hemophilia B and a normal 46,XX karyotype. Polymerase chain reaction and conformation sensitive gel electrophoresis techniques have been applied to the important regions of the factor IX gene,and an abnormal conformation sensitive gel electrophoresis profile was identified in exon 5 of the gene. After sequencing, the mutation was found to be C17761T (R116X) in homozygous form. Then, polymerase chain reaction-restriction fragment length polymorphism using the EcoRV restriction enzyme was applied for confirmation of the homozygous mutation in the proband and for carrier testing in the relatives. In addition, haplotype analysis was informative at the HhaI polymorphic site for the female patient.