VALUE OF DNA ANALYSIS WITH MULTIPLE DNA PROBES FOR THE DETECTION OF HEMOPHILIA-A CARRIERS

Detection of hemophilia carriers is an important issue and should be a ddressed with great care. The allelic frequencies of three intragenic probes (Bcl I for probe p114.12, Xba I for probe p482.6, and Bgl I for probe C) and one linked probe (Bgl II for probe DX 13) are reported, together with their diagnostic yield singly and in combination. In thi s series, 725 individuals (405 females) in 156 families were analyzed for restriction fragment-length polymorphisms. A total of 255 females (63 %) were found to be informative for their carrier state with one o r more probes. The most informative intragenic probe was p482.6 (usefu l in 49% of informative females). The most informative probe was DX 13 (useful in 59% of informative females), but this is a linked probe th at carries a 5% risk of cross-over. By the use of probes p114.12, p482 .6, and DX 13, almost 98% of all the informative females could be dete cted. In about 71% of families with a family history and a known carri er, prenatal diagnosis was feasible.