The molecular basis of hemophilia B

Abstract

Hemophilia B (HB) is a genetically determined bleeding disorder characterized by deficiency of the coagulation factor IX (FIX). The severity of bleeding phenotype is associated with FIX plasma level. More than 1200 F9 gene variants have been identified in hemophilia B patients at different locations which only confirms the marked heterogeneity of this bleeding disorder. The HB bleeding phenotype does not always correlate thoroughly with FIX:C plasma level, so identification of the molecular mechanism of HB may be helpful in understanding the heterogeneity of the hemorrhagic phenotype and may contribute to better diagnosis and therapy of the affected patients. This article presents the molecular determinants of hemophilia B and discusses their pathomechanisms in particular FIX domains.