Frequency of beta-globin gene mutations in beta-carrier couples in Babolsar, Iran, 2001-2011

Background and Beta-thalassemia is an autosomal recessive disease characterized by reduction or complete absence of beta-globin gene expression. This study aimed to find out and determine the spectrum of beta-globin gene mutations and especially rare mutation in beta-carrier couple in Babolsar, north region of Iran. This is very important in perinatal diagnosis of thalassemia. This descriptive study was carried out on 158 beta-carrier couples identified using hematologic testing in Babolsar thalasemia counseling center during years 2001-2011. They were referred to cytogenetic centers for consoling beta-globin gene mutations. Amplification-refractory mutation system-polymerase chain reaction (ARMS-PCR) and Restriction fragment length polymorphism (RFLP) were used for identification beta-globin gene mutations. More than 20 kinds of common mutations were studied on 316 individuals (632 chromosome), among them, mutation IVSII-1 (G>A) was the most common (72.4%). About 90% of mutations was consisted of four mutation, IVSII-1 (G>A), C22 (G>T), C30 (G>C), and C8 (-AA). 5% of mutations was consisted of rare mutations, C26 (HgbE), C6 (HgbS), IVSII-848 (C>A), and IVSI-130 (G>A, I). The most common beta-globin chain mutation was IVSII-1 (G>A) that is the same in Iran northern provinces (Guilan, Mazandaran, and Golestan). SCA (C60) and HgbE (C26) that are rare beta-globin gene mutations were seen this area, that are not seen in other regions of Iran.