AIMS: IVSII-666 (C-T) is one of the polymorphic sites located in the second intron of the β-globin gene. Its polymorphism rate and relationship to a specific mutation are studied for the first time on 211 DNA samples of thalassemia trait patients living in Mazandaran province in North Iran using Ssp1 restriction enzyme. β-Globin haplotype determination at XmnI/(G)γ, HincII/3'Ψβ, HinfI/5'β, RsaI/5'β, and SspI/β sites was also performed by analysis of family members. RESULTS: Nineteen different haplotypes were encountered in 211 unrelated thalassemia trait patients. One hundred twenty-seven patients (60.2%) were homozygous (+/+), 81 (38.4%) were heterozygous (+/-), and 3 (1.4%) were homozygous (-/-) for Ssp1 polymorphism. Of 24 mutant chromosomes negative for SspI, 16 were linked to mutation in codon 8(-AA). All codon 8(-AA) mutations were linked to the SspI-negative site. CONCLUSION: The SspI site can be used as a marker for tracking either normal β-globin gene (11.9%) or mutant alleles at codon 8 during prenatal diagnosis.
AIMS: IVSII-666 (C-T) is one of the polymorphic sites located in the second intron of the β-globin gene. Its polymorphism rate and relationship to a specific mutation are studied for the first time on 211 DNA samples of thalassemia trait patients living in Mazandaran province in North Iran using Ssp1 restriction enzyme. β-Globin haplotype determination at XmnI/(G)γ, HincII/3'Ψβ, HinfI/5'β, RsaI/5'β, and SspI/β sites was also performed by analysis of family members. RESULTS: Nineteen different haplotypes were encountered in 211 unrelated thalassemia trait patients. One hundred twenty-seven patients (60.2%) were homozygous (+/+), 81 (38.4%) were heterozygous (+/-), and 3 (1.4%) were homozygous (-/-) for Ssp1 polymorphism. Of 24 mutant chromosomes negative for SspI, 16 were linked to mutation in codon 8(-AA). All codon 8(-AA) mutations were linked to the SspI-negative site. CONCLUSION: The SspI site can be used as a marker for tracking either normal β-globin gene (11.9%) or mutant alleles at codon 8 during prenatal diagnosis.