Características fenotípicas dos pacientes com anemia falciforme de acordo com os haplótipos do gene da β5-globina em Fortaleza, Ceará

Abstract

We analyzed 47 patients living in Fortaleza, Ceará with clinical, laboratory and molecular diagnosis of sickle cell anemia, in order to provide information on the influence of the βS-globin gene haplotypes on the phenotypic characteristics of this disease. The evaluation of hematological values was performed using an automated blood cell counter and the levels of HbF were determined by the alkali denaturation technique. The DNA was isolated from leukocytes from a whole blood sample. The analysis of the haplotypes of the βS mutation was achieved by PCR-RFLP, with an assessment of six polymorphic restriction sites. The patients were divided in 5 groups according to the type of haplotype: Bantu/Bantu, Benin/Benin, Bantu/Benin, Bantu/Atypical and Benin/Atypical. The level of significance was set for a p-value < 0.05. In the comparison between the haplotypes and the hematological characteristics, statistically significant differences were seen only for the values of HbF and Ht. The levels of HbF were higher for the Benin haplotype, followed by the Bantu haplotype, which is in agreement with the literature. There were more painful episodes and pneumonia in Benin/Atypical haplotype than in Bantu/Atypical patients, and a higher rate of urinary tract infection in Benin/Atypical haplotype than in Benin/Benin haplotype individuals. There was no statistically significant difference between the Bantu/Bantu and Benin/Benin haplotypes in respect to clinical complications however the Bantu/ Bantu haplotype was associated to a higher frequency in all studied clinical events when compared to Benin/Benin haplotype patients. The results show that the type of βS-globin gene haplotype influences the phenotypic characteristics of patients with sickle cell anemia, therefore molecular techniques should be considered to identify the haplotype as an important diagnostic tool to predict the clinical status of these patients.