Polymorphism distribution of Int13, Int22, and St14 VNTRs in a Mexican population and their application in carrier diagnosis of hemophilia A

Abstract

Variable nucleotide tandem repeats (VNTR) Int13, Int22, and St14 were analyzed to determine polymorphic distribution in normal individuals from Mexico's central region and their efficacy in detecting hemophilia A carriers. Polymerase chain reaction (PCR) was carried out on 166 X chromosomes from unrelated Mexicans, and the same method was applied to detect carriers in hemophilia A families. Screening revealed the existence of at least eight different alleles for Int13, 4 alleles for Int22, and 10 alleles for St14. Their heterozygosity rates were 41.3%, 52.6%, and 83%, respectively. Compared to Caucasians, the Mexican population showed a markedly low heterozygosity rate for the Int13 marker. However, Int22 showed a heterozygosity that was similar to Turkish and Chinese populations. The St14 marker was the most informative in carrier diagnosis, and a new 680-bp allele not previously reported was detected. Carrier diagnosis was performed in 39 women from eight different hemophilia A families. Fifteen (38%) females were not carriers, 16 (41%) females were carriers, and 8 (21%) were homozygous. Determination of polymorphisms in VNTR markers revealed that St14 was the most useful for hemophilia A carrier detection in Mexico. Am.