RFLP analysis for diagnosis of haemophilia A in the German Democratic Republic.

The frequencies of Bcl I, Hind III and Xba I intragenic polymorphic sites in the population of the GDR were found to be 0.68, 0.38 and 0.48, respectively. No differences in composition and frequencies were detectable at DXS 52 locus in comparison with other Caucasian populations. A strong linkage disequilibrium between the intragenic Bcl I and Hind III sites could be confirmed. The observed heterozygosity for the flanking marker DXS 52 in combination with intragenic Bcl I and Xba I polymorphisms was 0.97. Using these three RFLPs, 122 females at risk in 41 independent haemophilia A families were investigated; 86 of them could be identified and 27 excluded as carriers; 9 females could not be classified. So far, four prenatal diagnoses in the first trimester of gestation have been performed by RFLP analysis.