Hemophilia B with inhibitor: molecular analysis of the subtotal deletion of the factor IX gene.

ABSTRACT

The structure of factor IX gene was analyzed in a hemophilia B patient with inhibitor. Genomic DNA, digested with a variety of restriction endonucleases, was hybridized with the cDNA and various genomic factor IX probes. A large subtotal deletion of the gene was observed. The borders of the deletion span from a approximately 125 nucleotide region within the last exon to an unknown domain at least 7.5 kb upstream from the first exon it thus involves approximately 33 kb of the factor IX locus. The abnormal gene was inherited by the daughter of the propositus, who showed both the normal and the deleted allele.