The contribution of DNA analysis to carrier detection and prenatal diagnosis of hemophilia A and B

Abstract

Developments in DNA technology have provided a novel means of carrier detection and prenatal diagnosis of hemophilia A and B. The collection of a large set of data has enabled us to evaluate the present feasibility and reliability of a diagnosis at the gene level and its contribution to methods already available. Since 1984, 533 potential and obligate carriers belonging to 170 families with hemophilia have been referred to us. By the combined use of pedigree analysis, coagulation assays, and DNA (RFLP) analysis, certainty about the carrier status has been markedly increased for the potential carriers. Although RFLP analysis revealed the possible origin of the mutation in many families with an isolated patient, uncertainty remained for quite a number of their female relatives because of the possible occurrence of germline mosaicism. Forty-one women requested prenatal diagnosis during one or more pregnancies. The short time interval between pregnancies, even after abortion of an affected fetus, proved that first-trimester prenatal diagnosis has become an acceptable option for women at risk. Recently, efficient methods for direct identification of mutations have been developed, and they may allow a definite diagnosis for all families with hemophilia in the near future.

Diagnosis of Hemophilia B Carriers Using Two Novel Dinucleotide Polymorphisms and Hha I RFLP of the Factor IX Gene in Japanese Subjects

“…The cloning of the factor IX gene and the identification of intragenic factor IX DNA polymorphisms have im proved carrier testing and prenatal diagnosis in affected pedigrees, especially in Caucasian populations. Direct sequencing of the factor IX gene, RFLP analysis by Southern blotting and PCR-based polymor phism analysis are used to diagnose carrier states (19). The direct se quencing of the factor IX gene is more accurate and is now generally preferred over the other two procedures.…”

Bleeding in carriers of hemophilia

“…1 In the early 1980s, it became possible to ascertain the carrier status by means of DNA analysis, which has evolved from haplotyping to mutation analysis offering certainty about the carrier status. 2 During the last 3 decades, genetic counseling, carrier testing, and prenatal diagnosis of hemophilia have become an integrated part of the comprehensive care for hemophilia. 3 Female carriers are expected to have a plasma concentration of factor VIII or IX corresponding to half the concentration found in healthy individuals, which is generally sufficient for normal hemostasis.…”

Analysis of the two microsatellite repeat polymorphisms of the factor VIII gene in the Turkish population

“…The disease results from mutations in the factor VIII (FVIII) gene which is located in the Xq28 region spanning 186 kb and consisting of 26 exons that code for 9 kb mRNA ( Gitschier et al , 1984 ). Genetic counselling for haemophilia A has been widely carried out for more than a decade by the use of DNA linkage markers ( Broker‐Vriends et al , 1992 ) and several intragenic RFLPs have been identified and used in linkage analysis ( Green et al , 1991 ). The presence of tight linkage between some markers and the unavailability of PCR primers for some restriction sites, limits the use of RFLPs in tracking the defective allele ( Peake et al , 1993 ).…”