HBB gene cluster haplotype diversity in sickle cell anemia patients of Chhattisgarh, India

Sickle cell anemia (SCA) is one of the hereditary hemoglobin disorders in Indian populations. An exceptionally high prevalence of SCA is observed in the populations of Chhattisgarh. Restriction fragment length polymorphism (RFLP) haplotypes of the beta globin (HBB) gene cluster are important as population data, anthropological purpose for tracing migration of SCA allele and predicting the severity of SCA disease. The purpose of this study was to elucidate the HBB haplotypes and their correlation with clinical and hematological profile of SCA patients of Chhattisgarh population. The HBB gene cluster haplotypes were determined in 190 SCA patients by the polymerase chain reaction-restriction fragment length polymorphism method. Medical records of patients were reviewed to obtain pertinent clinical features, hemoglobin fractions, and other biochemical variables. Among the analyzed patients, 74% had Arab-Indian (AI) haplotype, followed by 21% atypical haplotypes. Senegal, Benin, and Cameroon types of HBB haplotypes represented 3%, 1%, and 1% of the patients, respectively. Comparison of various biochemical and hematological variables and clinical complications among various haplotypes did not reveal significant differences. The high frequency of atypical haplotypes observed may have been generated by single and double crossing-over between AI haplotype and normal HBB haplotype. Considering the Indian population’s genetic structure and diversity, the results of our study should be considered as introductory, and our study can serve as a possible tool for additional studies of SCA in India.