Haplotypes βs-globin and its clinical-haematological correlation in patients with sickle-cell anemia in Triângulo Mineiro, Minas Gerais, Brazil

Haplótipos da βs-globina e sua correlação clínica-hematológica em portadores de anemia falciforme no Triângulo Mineiro, Minas Gerais, Brasil

ABSTRACT

Introduction:

Sickle-cell anemia (SCA) is the most severe form of sickle-cell disease, and is characterized by homozygous hemoglobin S (α2β^S2).

Objective:

Determine the haplotypes frequency in patients with SCA and their correlation with clinical and hematological profile.

Method:

We performed a retrospective descriptive study by reading the charts and a cross-sectional study for molecular analysis to determine the haplotypes of the gene βS globin in 61 patients with sickle-cell anemia (SS) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), using restriction endonucleases Xmn I, Hind III, Hinf I and Hinc II for analysis of six polymorphic sites in the beta cluster.

Result:

The genotypes were Central African Republic (CAR)/CAR (60.8%), CAR/Benin type (BEN) (13.1%), CAR/ Cameroon type (CAM) (1.6%), CAR/atypical (ATP) (13.1%), BEN/BEN (13.1%), BEN/ATP (4.9%) and ATP/ATP (3.3%). Among the analyzed chromosomes, 64.8% were CAR type, 22.1% were BEN, 12.3% ATP and 0.8% CAM. Levels of fetal hemoglobin (HbF) were significantly lower in CAR/CAR than in ATP/ATP, BEN/ATP and CAR/BEN. No association was observed between the different genotypes and clinical manifestations.

Conclusion:

Despite the lack of association between genotypes and clinical profiles, higher frequency of clinical events was observed in patients with at least one type of CAR chromosome. A significant association was also observed between lower average levels of HbF and CAR/CAR genotype compared to other genotypes.

Key words:
sickle-cell anemia; haplotypes; fetal hemoglobin