Molecular cloning of the gene for human anti-haemophilic factor IX

A functional deficiency of factor IX, one of the coagulation factors involved in blood clotting¹, leads to the bleeding disorder known as Christmas disease², or haemophilia B. Both this disease and haemophilia A (factor VIII (C) deficiency) are X chromosome-linked and together occur at a frequency of ~1 in 10,000 males. The molecular basis for the functional alteration of factor IX in Christmas disease is not clearly understood. As a first step towards the elucidation of the molecular events involved, we have attempted molecular cloning of the factor IX gene. We used a bovine factor IX cDNA clone, isolated using synthetic oligonucleotides as probes, to screen a cloned human gene library. Here we report the isolation and partial characterization of a λ recombinant phage containing the human factor IX gene.