| Abstrakt: |
Carrier frequency of the βS allele has been reported to be 0.19% in Mazandaran province, northern Iran. Haplotype analysis of the βS allele helps trace the origin of its encoded hemoglobin (Hb) variant, Hb S, in a region. The aim of this study was to investigate the haplotypes associated with βS alleles in Mazandaran province. Capillary electrophoresis was carried out to detect individuals suspected to have a βS allele(s). DNA analysis (PCR-RFLP) was used for final confirmation. To identify 5' to 3' β-globin gene cluster haplotypes associated with βS alleles, family linkage analysis was applied. Six polymorphic sites (HincII 5' to ε, XmnI 5' to G947;, HindIII in G947;, HindIII in Aβ, HincII 3' toψβ and AvaII in β) were investigated using the PCR-RFLP method. Five different haplotypes were linked to βS alleles, while βA alleles were associated with nine haplotypes. Among the βS alleles, 53.9% were associated with the Benin (----++) haplotype, and the Arab-Indian (+++-++) haplotype had the second-highest frequency (23%). Unlike southern provinces, where the Arab-Indian haplotype is prominent, the Benin haplotype is the most frequent haplotype in northern Iran, and this may represent a founder effect. Since the Benin haplotype does not carry the XmnI polymorphism 5' to the G947; gene, which is responsible for high expression of Hb F, a severe form of sickle cell disease can be anticipated in patients that are homozygous for the βS allele in the northern region. [ABSTRACT FROM AUTHOR] |
