Distribution of β-Globin Gene Mutations in Thalassemia Minor Population of Kerman Province, Iran.

BACKGROUND

Mutations in β-globin gene may result in β-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 β-thalassemia) of heterozygote couples.

METHODS

Couples with high hemoglobin A(2) and low mean corpuscular volume were studied as suspicious of β-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 β-globin gene mutation in the people who involved with β-thalassemia minor in this province.

RESULTS

Among the 266 subjects, 17 different types of mutation in β-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 βnt30 (T>A) were accounted for 19.5%. Unknown alleles comprised 3.4% of the mutations.

CONCLUSION

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.