Distribution of beta-globin gene mutations in thalassemia minor population of Kerman Province, Iran

ABSTRACT

Mutations in beta-globin gene may result in beta-thalassemia major, which is one of the most common genetic disorders in Iran and some other countries. Knowing the beta-globin mutation spectrum improves the efficiency of prenatal diagnosis in the affected fetuses [major beta-thalassemia] of heterozygote couples. Couples with high hemoglobin A2 and low mean corpuscular volume were studied as suspicious of beta-thalassemia carriers in Genetic Laboratory of Afzalipour Hospital, Kerman, Iran. We used amplification refractory mutation system, reverse hybridization, and DNA sequencing to determine the spectrum of beta-globin gene mutation in the people who involved with beta-thalassemia minor in this province. Among the 266 subjects, 17 different types of mutation in beta-globin gene were identified. Three of the mutations account for 77.1% of the studied cases. IVSI-5 [G>C] was the most frequent mutation [66.2%] followed by IVSII-I [G>A] [6%] and Fr 8-9 [+G] [4.9%]. The less frequent mutations include IVSI-6 [T>C], codon 15 [G>A], codon 44 [-C], codon 39 [C>T], codon 8 [-AA], codon30 [G>C], IVSI-110 [G>A], codon 36-37 [-T], 619bp deletion, codon 5 [-CT], IVSI-25bp del, codon 41-42 [-TTCT], IVSI-I [G>A], and beta nt30 [T>A] were accounted for 19.5%. Unknown alleles comprised 3.4% of the mutations. However, the frequencies of different mutations reported here are significantly different from those found in other part of the world and even other Iranian provinces. Reporting a number of these mutations in the neighboring countries such as Pakistan can be explained by gene flow phenomenon