Clinical and molecular characteristics of sickle cell anemia in the northeast of Brazil

ABSTRACT

Beta S-globin gene (âS-globin) haplotypes, markers for severe sickle cell anemia (SCA), and the alpha-thalassemia 2 gene 3.7 kb deletion (-á2(3.7 kb) thal) along with demographic and clinical data were investigated in SCA outpatients (n = 125, 63 female and 62 male) in the Brazilian state of Bahia, which has a high prevalence SCA. PCR-RFLP showed that the Central African Republic/Benin (CAR/BEN, 51.2 percent) haplotype was most frequent, followed by the Benin/Benin (Ben/Ben, 28.8 percent). At least one CAR haplotype was present in every outpatient with a history of cerebrovascular accident. The Cameroon (Cam), Senegal (Sen) and Arab-India haplotypes occurred in small numbers, as did atypical haplotypes. Fetal hemoglobin (HbF, percent) was unevenly distributed. Compared to those > 18 y, those aged < 18 y had had fewer erythrocyte transfusions and high HbF levels (12.3 percent ± 7.01 to 7.9 percent ± 4.36) but a higher frequency of spleen sequestration and pneumonia. Compared with normal á - genes carriers values, the outpatients with -á2(3.7 kb) thal (determined by PCR analysis) had significantly higher mean hemoglobin concentration (Hb) (8.3 ± 1.34 g/dL, p = 0.018) and packed cell volume (PCV = 27.1 percent ± 4.26, p = 0.019) but low mean corpuscular volume (MCV = 86.1 fL = 10-15 L ± 9.56, p = 0.0004) and mean corpuscular hemoglobin (MCH = 26.6 percent ± 4.60, p = 0.039).