Xmn1-158 γGvariant in B-thalassemia intermediate patients in South-East of Iran

Background: xmn-1 polymorphism of γgglobin gene (hbg2) is a prominent quantitative trait loci (qtl) in β-thalassemia intermediate (β-ti). in current study,we evaluated the frequency of xmn-1 polymorphism and its association with β-globin gene (hbb) alleles and hb f level in β-ti patients in sistan and balouchestan province,south-east of iran. subjects and methods: 45 β-ti patients were enrolled. hbb gene mutations and xmn-1 polymorphism were determined by amplification-refractory mutation system (arms) pcr method. hemoglobin profile was determined using capillary electrophoresis. results: the study participants consisted of 26 (58%) males and 19 (42%) females.mean age of the patients was 10.7±3.1 years old. overall,xmn-1 polymorphism was observed in 28 (62%) patients. homozygous (tt) and heterozygous (ct) genotypes of the polymorphism represented with frequencies of 12 (26%) and 16 (35%),respectively. main recognized hbb gene mutation was ivsi-5(g>c) with homozygous frequency of 44%. non-zero (β+) alleles of hbb gene constituted 11.1 % (4 patients with heterozygous β+ and one with homozygous β+ genotype). hb f level was significantly higher in patients with at least one xmn-1allele (67.9±17.9%) than those without the polymorphism (19.5±20.3%,p<0.0001). also,patients with homozygous genotype demonstrated significantly higher hb f compared to heterozygous (ct) cases (respective percentages of 85±6.8 and 54.7±10.5,p<0.0001). conclusion: our results highlighted the role of xmn-1 polymorphism as the main phenotypic modifier in β-ti patients in sistan and balouchestan province. © 2017,tehran university of medical sciences (tums). all rights reserved.