A DNA polymorphism in the coding region of coagulation factor IX-- potentially valuable for carrier detection, prenatal diagnosis, and population studies--was described in 1985. It had been discovered with monoclonal antibodies that distinguish between threonine and alanine as the 148th residue of the peptide. Its use as a diagnostic tool has been limited because threonine-containing factor IX (Malmo A) is dominant to alanine-containing factor IX (Malmo B) in immunoassays of plasma; therefore, detection of Malmo heterozygotes is not possible in all instances. A DNA method for recognizing all heterozygotes has been developed, but it also has limitations. We report the development of another DNA procedure based on amplification of the relevant DNA with the polymerase chain reaction (PCR). This method is quick, avoids the use of isotopes and x-ray film, and specifically identifies all the Malmo genotypes: hemizygotes, homozygotes, and heterozygotes. The procedure can be performed satisfactorily on small samples of blood (less than 1 mL) as suggested by Kogan et al (N Engl J Med 317:985, 1987). The method described is applicable to any genetic polymorphism that overlaps a restriction enzyme recognition site.

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.

Five independent alloantibodies directed to factor VIII coagulant antigen (VIII:CAg) were assessed against normal, von Willebrand's disease, and severe hemophilia A plasmas. Immunoradiometric assays (IRMAs) were developed for each antibody, one of which had arisen “spontaneously” and four in transfused hemophiliacs. The correlations between assays were very high for normal, vWd, and both CRM+ and CRM- hemophiliacs. This suggests that IRMAs maybe developed from almost any reasonably high titered alloantibody and used with confidence in diagnosing CRM- hemophilia A in utero by fetoscopy.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.