Replacement of a partial denture: a conservative approach.
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Adult↗
Biomedical subjects
D J Rees
Publications and source records attributed to D J Rees.
Characterisation and use of an intragenic polymorphic marker for detection of carriers of haemophilia B (factor IX deficiency).
DNA from 33 healthy White subjects was analysed with a 2 X 5 kilobase subgenomic DNA probe derived from the gene for coagulation factor IX, containing the exon "d" region of that gene. Intragenic Taq I restriction-fragment length polymorphism was revealed, with allelic frequencies estimated at 0 X 65 and 0 X 35 (SE = 0 X 06), also detectable by a cDNA probe. The genomic DNA probe is technically superior to the cDNA probe and has been used in three families with haemophilia B (factor IX deficiency). The polymorphic marker segregates with the deleterious mutation, allowing the identification or exclusion of carriers. The allelic frequencies of the Taq I polymorphism are virtually ideal. Therefore, such a polymorphism should be helpful both in genetic counselling of approximately 40% of affected families and in prenatal diagnosis.
Alleles↗
The gene structure of human anti-haemophilic factor IX.
The mRNA sequence of the human intrinsic clotting factor IX (Christmas factor) has been completed and is 2802 residues long, including a 29 residue long 5' non-coding and a 1390 residue long 3' non-coding region, but excluding the poly(A) tail. The factor IX gene is approximately 34 kb long and we define, by the sequencing of 5280 residues, the presumed promoter region, all eight exons, and some intron and flanking sequence. Introns account for 92% of the gene length and the longest is estimated to be 10 100 residues. Exons conform roughly to previously designated protein regions, but the catalytic region of the protein is coded by two separate exons. This differs from the arrangement in the other characterized serine protease genes which are further subdivided in this region.
Amino Acid Sequence↗
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 clotting, leads to the bleeding disorder known as Christmas disease, or haemophilia B. Both this disease and haemophilia A (factor VIII (C) deficiency) are X chromosome-linked and together occur at a frequency of approximately 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 lambda recombinant phage containing the human factor IX gene.
Bacteriophage lambda↗
Gene deletions in patients with haemophilia B and anti-factor IX antibodies.
Christmas disease, or haemophilia B, is an inherited X-linked haemorrhagic disease which at present occurs in 798 known cases in the United Kingdom, corresponding to a frequency of about 1 in 30,000 males. Patients are deficient in the intrinsic clotting factor IX and are treated by replacement of this protein prepared from pooled plasma obtained from normal individuals. Occasionally treatment is complicated by the appearance of specific anti-factor IX antibodies. It seemed to us that this might be due to the absence of 'self' factor IX causing the immune system to regard the infused normal factor IX as foreign. The absence of all or part of the factor IX gene was an obvious possible reason for this, which we have now tested using our previously isolated gene probe. We have found four patients with gross gene defects.
Autoantibodies↗
Haemophilia B caused by a point mutation in a donor splice junction of the human factor IX gene.
Haemophilia B (Christmas disease) is an inherited, recessive, sex-linked, haemorrhagic condition caused by a defect in the intrinsic clotting factor IX. This disease occurs in males at a frequency of approximately 1 in 30,000. Patients differ in the severity of their clinical symptoms, and variation in the clotting activity and in the concentration of factor IX antigen in their plasma has been demonstrated. There is probably heterogeneity in the molecular defects of the factor IX gene causing the disease. Here we study a severely affected, antigen-negative patient, and show that the only significant sequence difference from the normal factor IX gene is a point mutation changing the obligatory GT to a TT within the donor splice junction of exon f. We infer that this change is the cause of the disease in this individual. In addition, we have used oligodeoxynucleotide probes specific for this mutation to demonstrate the feasibility of carrier detection and prenatal diagnosis for relatives of the patient.
Base Sequence↗