Abstract
Heterogeneous mutations in the coagulation factor IX (FIX) gene result in a bleeding tendency known as haemophilia B. The haemophilia B mutation database has a total of 2353 patient entries, including 10 of the estimated 1000 Turkish patients. In this study, a more comprehensive analysis of the molecular pathology of haemophilia B in Turkey revealed one large deletion and 33 point mutations in the FIX gene of 34 unrelated patients. Haplotype analysis using six polymorphic sites showed that the mutations identified in a total of 45 patients occurred on 13 different haplotypes and that each mutation was family specific.