βS haplotypes: Genetic profile and association with biochemical parameters in individuals with Sickle cell anemia in Western Bahia, Brazil

Abstract

Sickle cell anemia (SCA) is a hemoglobinopathy with a heterogeneous clinical presentation that, in part, results from complex interactions between genetic factors, some of which are explained by haplotypes in the β-globin (β^S) gene cluster. This study identified the main haplotypic profiles of individuals with SCA in Western Bahia, Brazil, and evaluates the possible relationship between the genetic profile associated with haplotype inheritance and clinical follow-up parameters presented by the individuals participating in the study. The Bantu/Benin genotype was more frequent, although it did not show a statistically significant difference compared to the Bantu/Bantu genotype. As described in other locations in Brazil, the Bantu chromosome was the most frequent in this study (59 %), which supports the data on the formation and dynamics of the population concerning the geographical origin of the enslaved Africans trafficked to the capital of Western Bahia. Important hematological parameters, such as HbF, biochemical parameters associated with the hemolysis process, and phenotype severity, such as lactate dehydrogenase, aspartate aminostransferase, and direct bilirubin, were related to the Bantu/Bantu genotype. HbF levels were 4× lower, and biochemical parameters were up to 2.5× higher in Bantu/Bantu individuals who did not use hydroxycarbamide (HC) compared to carriers of the Bantu/Bantu genotype who used HC. The results indicate the importance of assessing the inheritance of β^S-haplotypes to help understand the phenotype and the relevance of HC use in the context of SCA.