Association between beta globin haplotypes, HBBP1 and HMOX1 polymorphisms in relation to HbF among sickle cell anemia patients: a study in Southwest Iran

Abstract

The haplotypes of β-globin gene cluster in patients with sickle cell anemia are associated with different clinical manifestations and fetal hemoglobin (HbF) levels. In addition, SNP in some genes within the β-globin gene cluster (HBBP1) and outside it (HMOX1) has been recently reported to be related to HbF levels. In this study, rs2071348 and rs2071746 polymorphisms in HBBP1 and heme oxygenase 1 (HMOX1) genes associated with different haplotypes and HbF levels in patients with sickle cell anemia were evaluated in comparison with healthy subjects. In this case-control study, 150 patients with sickle cell anemia (90 homozygous and 60 sickle-cell trait) were evaluated and compared with 50 healthy individuals referred to Shafa tertiary hospital in Ahvaz city of Khuzestan Province, Iran. HbF level was measured by alkali and acid electrophoresis. PCR-RFLP and ARMS-PCR methods were used to determine β-globin gene haplotypes and HBBP1 gene polymorphism, respectively. Arab-Indian was the most common genotype found in both homozygous and sickle-cell trait patients with a respective prevalence of 55.5 and 50% followed by homozygous Benin with 11.1 and 18.3% prevalence, respectively. The highest and lowest level of HbF were observed in Arab-Indian (24.1 ± 6.35) and Benin/Benin haplotypes (7.63 ± 2.29), respectively. A significant relationship was found between HbF level with rs2071746 A>T polymorphism of HMOX1 gene (P < 0.019) as well as with rs2071348 polymorphism of HBBP1 gene (P < 0.034). However, there was no significant relationship between haplotypes with gene polymorphisms. Arab-Indian was the most common haplotype in this region. The HbF level was significantly higher in patients with Arab-Indian haplotype, patients with C genotype in rs2071348 polymorphism locus of HBBP1 gene, and patients with T genotype in rs2071746 polymorphism locus of HMOX gene.