[Molecular analysis of hemophilia A in families of Northeastern Mexico].

We analysed DNA through Southern blot and polymerase chain reaction using blood samples of northeastern Mexican families affected by hemophilia A. Our aim was to identify possible carriers of the mutated gene by indirect detection using the Bcl I polymorphism (RFLP) at intron 18 of the factor VIII gene. The sample studied consisted of 43 individuals within eight families with hereditary hemophilia A. Of 17 possible carrier women, three were positive, five were negative, and in the remaining nine, the lack of informativeness (heterozygosity for the polymorphism) of their mothers precluded reaching conclusions. The frequencies found for the Bcl I polymorphism were 63% for the 1.2 kb allelic fragment and 37% for the 0.9 kb allelic fragment. Heterozygote women were found in 48.2% of the families studied. Our results show that probably, the Bcl I RFLP is more useful for HA carrier diagnosis in our sample (northeastern Mexico).