In genotyping a severe hemophilia B subject, exons 1-3 and 5-8 were normal. Exon 4 did not amplify, suggesting a partial gene deletion. Previously, a French family with an exon 4 deletion had severe haemophilia B with a circulating, dysfunctional factor IX protein missing its first growth factor-like domain; breakpoints were not analyzed. Using a 5' primer for exon 3 and a 3' primer for exon 5 ...

We have used the polymerase chain reaction to amplify the entire coding region of canine factor IX from a hemophilia B animal. When the sequence was compared to that which codes for normal canine factor IX, a single missense mutation was identified. This mutation (G----A at nucleotide 1477) results in the substitution of glutamic acid for glycine-379 in the catalytic domain of the molecule. The...

We used a first-generation adenovirus vector (AVC3FIX5) to assess whether human factor IX could be expressed and detected in the rhesus macaque, which we have shown does not make high-titer antibodies to human factor IX protein. Three animals received 1 x 10(10) to 1 x 10(11) plaque-forming units per kilogram by intravenous injection. Human factor IX was present within 24 hours of vector admini...

Factor IXAlabama is a variant factor IX molecule responsible for a clinically moderate form of hemophilia B. Twenty-five kilobases (kb) of the variant gene, including seven exons coding for the structural protein, were cloned and characterized. The restriction map and the arrangement of coding regions are identical to those of the normal gene. DNA sequence analysis of the coding regions reveale...

Factor IX is a multidomain protein and is the proenzyme of a serine protease, factor IXa, essential for hemostasis. In this report, we describe the molecular basis of hemophilia B (deficiency of factor IX activity) in five patients who have neither deletions nor rearrangements of the factor IX gene. By enzymatic amplification and sequencing of all exons and promoter regions, the following causa...

Inherited diseases might be treated by introducing normal genes into a patient's somatic tissues to correct the genetic defects. In the case of hemophilia resulting from a missing clotting factor, the required gene could be introduced into any cell as long as active factor reached the circulation. We previously showed that retroviral vectors can efficiently transfer genes into normal skin fibro...

The study of coagulation factors has been rapidly advanced by studies performed in genetically engineered mouse strains. Investigation of factor IX (FIX) has benefited from excellent gene-deleted mouse models that recapitulate many of the features of human haemophilia B. Moreover, advanced positional cloning techniques and availability of technology to allow not only knock-out mice, but also kn...

Hemophilia B Leyden is characterized by low levels of factor IX antigen and activity before the age of 15, whereas after puberty factor IX levels rise at a rate of about 5% per year. A single base substitution (-A----T) at position -20 was identified in the putative promoter of the gene cloned from a patient with hemophilia B Leyden. This nucleotide change was confirmed in a second patient from...

Haemophilia B is an X-linked recessive bleeding disorder, arising from a deficiency of coagulation factor IX. It has been a target for gene therapy ever since the factor IX gene was cloned in 1982. Several distinct approaches have been evaluated in humans over the last 30 years, but none has resulted in tangible corrections of the bleeding phenotype in humans until recently. Our group has now s...