| 1. |
- Ljung, R, et al.
(författare)
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Genetic variants of haemophilia B detected by immunoradiometric assay : implications for prenatal diagnosis
- 1982
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Ingår i: Pediatric Research. - : Springer Science and Business Media LLC. - 0031-3998 .- 1530-0447. ; 16:3, s. 8-256
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Tidskriftsartikel (refereegranskat)abstract
- Fifty patients with haemophilia B, belonging to 29 kindreds, were investigated with a highly sensitive immunoradiometric assay based on a homologous antibody to factor IX. The assay measures factor IX antigen (f.IX:Ag) in plasma down to 0.025 U/dl. Seventeen of 18 investigated patients with severe haemophilia B had very little or no f.IX:Ag. Also four of nine patients with moderately severe disease had very low antigen levels, approximately equal to their factor IX clotting activity (f.IX:C), whereas the other 5 had antigen in excess of activity. Of the 23 investigated patients with mild haemophilia B, 20 had f.IX:Ag approximately equal to f.IX:C, whereas 3 had normal amounts of antigen. One family with mild disease was found to have a possible variant of haemophilia B Leyden, earlier described in a few families with moderately severe disease. No haemophilia BM variants, characterized by prolonged prothrombin time with bovine brain thromboplastin, were found. We have shown earlier that the immunoradiometric assay of f.IX was useful in the prenatal evaluation of one fetus at risk for haemophilia B. The present study shows that the assay can be applied for prenatal diagnostic purposes in the vast majority of carriers of severe haemophilia B and in about half of the carriers of moderately severe disease.
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| 2. |
- Ljung, R, et al.
(författare)
-
Haemophilia A and B--two years experience of genetic counselling and prenatal diagnosis
- 1982
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Ingår i: Clinical Genetics. - : Wiley. - 0009-9163 .- 1399-0004. ; 22:2, s. 70-75
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Tidskriftsartikel (refereegranskat)abstract
- Haemophilia A. Thirty-one pregnant women, obligate or probable carriers of haemophilia A, requested prenatal diagnosis if sex determination showed the foetus to be a male. In 11 of the 31 cases the foetuses were females; in two, the genetic variant of the disease rendered prenatal diagnosis impossible; and in two, the mother aborted spontaneously. From the remaining 16 male foetuses, blood samples were obtained in utero in the 17th to 20th week of gestation. Examination of the samples showed that 11 of the foetuses were unaffected and five affected. Haemophilia B. Three carriers of haemophilia B had male foetuses. Examination of foetal blood obtained in utero showed that these three foetuses were affected. Confirmation. All women with an affected foetus requested termination of pregnancy. In one of the cases of abortion, no blood was obtained for confirmative examination. In the remaining cases, the prenatal prediction was confirmed in the abortus or in the child after birth; three women are still pregnant.
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| 3. |
- Ljung, Rolf, et al.
(författare)
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Immunoradiometric assay of inhibitors of antihaemophilic factor A
- 1982
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Ingår i: Acta Paediatrica Scandinavica. - 0001-656X. ; 71:6, s. 1019-1023
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Tidskriftsartikel (refereegranskat)abstract
- An immunoradiometric assay (IRMA) for determination of antibodies against f. VIII:C in haemophilia A was developed. The assay was based on competitive binding of radiolabelled anti-VIII:C and antibodies in the test material to immobilized VIII:C. Fifteen haemophiliacs with known inhibitors were investigated with the new method and with a conventional neutralization test. In 3 cases the inhibitors were detected only with the IRMA and in the other 12 there was good agreement between the inhibitor levels found with the two methods. It was also possible to demonstrate the antibodies in three non-haemophilic patients with acquired inhibitors. The IRMA, which can detect the antibodies down to a concentration of 0.02 inhibitor units per ml, is more sensitive than conventional neutralization tests and is thus of practical importance in the investigation of patients with low inhibitor titres.
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