| 1. |
- Graham, J. B., et al.
(författare)
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The Malmo polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms
- 1988
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Ingår i: American Journal of Human Genetics. - 0002-9297. ; 42:4, s. 573-580
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Tidskriftsartikel (refereegranskat)abstract
- A mouse monoclonal antibody (MAB 9,9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism - Thr:Ala - at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148(thr)) are designated Malmo A, and negative reactors (148(ala)) are designated Malmo B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmo A in AB women is approximately half that of AA women, and 'lyonization' is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over - including double crossing-over - appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ~50% of the AB women in the pool of Malmo A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmo epitope if the studies were limited to men.
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| 2. |
- Graham, J B, et al.
(författare)
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Carrier detection in hemophilia A : a cooperative international study. I. The carrier phenotype
- 1986
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Ingår i: Blood. - 0006-4971. ; 67:6, s. 9-1554
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Tidskriftsartikel (refereegranskat)abstract
- Eight laboratories in six countries cooperated to clarify several issues concerning the phenotypes of heterozygous carriers of hemophilia "A." Plasma levels of factor VIII (F.VIII:C, formerly VIII:C) and von Willebrand factor (VWF:Ag, formerly VIIIR:Ag) of carriers and normal women were determined by various "in-house" methods; a single lyophilized plasma standard was used for all assays. Analysis of the collated data from 336 carriers (296 obligatory carriers and 40 sporadic carriers) and 137 normal women showed that there was no difference in the F.VIII:C levels of "paternal" carriers (women who had obtained the abnormal gene from their fathers) and "maternal" carriers. Neither was there a difference in the VWF:Ag levels of normal women and either type of carrier. Age was found to have a significant effect on both F.VIII:C and VWF:Ag, values being higher at very young and very old ages, the minima occurring in the 25- to 30-year range. ABO blood type had a striking effect. Women of types A, B, and AB (designated non-O in the study), both normals and carriers, had significantly higher levels of both factors than did women of type O. Analysis by laboratories showed that differences in mean levels of both factors between laboratories were highly significant. It was concluded that age, ABO blood type, and laboratory variation should be taken into account in carrier detection.
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| 3. |
- Green, P P, et al.
(författare)
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Carrier detection in hemophilia A : a cooperative international study. II. The efficacy of a universal discriminant
- 1986
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Ingår i: Blood. - 0006-4971. ; 67:6, s. 7-1560
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Tidskriftsartikel (refereegranskat)abstract
- Factor VIII (F.VIII) and von Willebrand factor (VWF):Ag data collected by eight laboratories on a total of 336 obligatory carriers of hemophilia A and 137 normal women were used to answer several questions concerning the construction of linear discriminants for carrier detection. It was found: that a "universal" linear discriminant can be constructed which is suitable for use in all laboratories and is nearly as effective as laboratory-specific discriminants; that inclusion of age and ABO blood type data improved the efficacy of these discriminants; that substitution of alternative assays for F.VIII and VWF:Ag did not generally improve the efficacy of the discriminants over that obtained using the bioassay for F.VIII:C and Laurell's immunoassay for VWF:Ag; that linear discriminants were far more effective than discriminants based on the F.VIII:C/VWF:Ag ratio. A step-wise procedure is given which any laboratory may follow in using the universal discriminant for carrier detection.
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