β<sup>S</sup>‐gene‐cluster haplotypes in sickle cell anemia patients from two regions of Brazil

Costa, Fernando Ferreira; Arruda, Valder R.; Gonçalves, Maria Gisele; Miranda, Sílvia R.P.; Carvalho, Maria Helena; Sonati, M.F.; Saad, Sara Olalla; Gesteira, F.; Fernandes, Dilson J.; Nascimento, Melise  Lemos; Queiroz, I. L.

doi:10.1002/ajh.2830450120

Cited by 24 publications

(19 citation statements)

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“…In contrast to previous reports, a significant increase in HbF level in Bantu patients after HU use was observed [3,4,8]. Perhaps this observation should be interpreted with caution due to the larger number of Bantu patients in our study.…”

Section: Discussioncontrasting

confidence: 99%

“…In this study, we confirmed prior reports among the Brazilian population which showed a high incidence of Bantu haplotype, due to migration features of Brazilian black population [7,8].…”

Section: Discussionsupporting

confidence: 92%

“…Several studies have been performed about determinants of response to HU such as b S haplotype [2][3][4][7][8][9]. In this study, we confirmed prior reports among the Brazilian population which showed a high incidence of Bantu haplotype, due to migration features of Brazilian black population [7,8].…”

Section: Discussionsupporting

confidence: 90%

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Effects of hydroxyurea in a population of Brazilian patients with sickle cell anemia

2005

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Fetal hemoglobin (HbF) inhibits the polymerization of sickle hemoglobin, modulating the clinical features of sickle cell anemia (SCA). Hydroxyurea (HU) therapy can increase the HbF level, although its production can be influenced by genetic determinants. Twentytwo Brazilian SCA patients were evaluated over 5 years before and after HU use. We analyzed (1) b S haplotype; (2) patient characteristics; and (3) toxicity. No differences between age, sex, and HU response were observed. We found 40.9% of homozygous for Bantu haplotype, and, in contrasting to other trials, we observed HbF level increase in this group (3.84-9.08 g/dL, P = 0.003). Adverse effects were rare. Labyrinthitis was observed in 2 (9.10%) patients after HU use, although this complication had not been described before. Am.

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Section: Discussioncontrasting

confidence: 99%

“…In this study, we confirmed prior reports among the Brazilian population which showed a high incidence of Bantu haplotype, due to migration features of Brazilian black population [7,8].…”

Section: Discussionsupporting

confidence: 92%

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Effects of hydroxyurea in a population of Brazilian patients with sickle cell anemia

2005

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“…However, our results do not agree with some previous published data (Bunn and Forget, 1986;Costa et al, 1994;Lugo et al, 2003) on HbF levels and β S -globin gene haplotypes but are consistant with some other reports (Falusi and Kulozik, 1990;Mouele et al, 1999;Inati et al, 2003). In our study, the presence of high HbF levels for the CAR/CAR haplotype could be due to sequence variations in regulatory regions, such as the 5'HS2 and flanking region of the γ gene (Lanclos et al, 1991;Ofori-Acquah et al, 2001).…”

Section: Discussioncontrasting

confidence: 57%

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

Adôrno

Zanette²,

Lyra³

et al. 2008

Genet. Mol. Biol.

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Beta S-globin gene (β S -globin) haplotypes, markers for severe sickle cell anemia (SCA), and the alpha-thalassemia 2 gene 3.7 kb deletion (-α 2 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%) haplotype was most frequent, followed by the Benin/Benin (Ben/Ben, 28.8%). 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, %) was unevenly distributed. Compared to those > 18 y, those aged ≤ 18 y had had fewer erythrocyte transfusions and high HbF levels (12.3% ± 7.01 to 7.9% ± 4.36) but a higher frequency of spleen sequestration and pneumonia. Compared with normal α -genes carriers values, the outpatients with -α 2 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% ± 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% ± 4.60, p = 0.039).

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“…The ethnic origin of the Brazilian population is highly heterogeneous (Alves-Silva et al 2000;CarvalhoSilva et al 2001) and the distribution of b-globin gene haplotypes in our SCD patients differs from that in the USA and Jamaica, where most studies of the clinical expression of the disease have been carried out (Costa et al 1994;Figueiredo et al 1996). This varied genetic background makes the study of ocular vessel alterations in Brazilian SCD patients of special interest, and raises the possibility of achieving additional insights into the clinical, laboratory and genetic modulation of this aspect of the disease.…”

Section: Introductionmentioning

confidence: 87%

Risk factors for conjunctival and retinal vessel alterations in sickle cell disease

Lima

Rocha

Silva

et al. 2006

Acta Ophthalmologica Scandinavica

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Purpose: The aim of this study was to clarify whether the clinical, laboratory and genetic aspects of sickle cell disease (SCD) influence the occurrence of vessel alterations in the conjunctiva and retina. Methods: A total of 102 SCD patients underwent biomicroscopical and retinal examination, in addition to evaluations of haemoglobin (Hb) and haematocrit (Ht) levels, fetal haemoglobin (HbF) estimations, serum creatinine and albuminuria levels, glomerular filtration rate (GFR) values, phenotypes, b-globin gene haplotypes and a-thalassaemia. The relationship between ocular vessel alterations and clinical, laboratory and genetic features were evaluated using chisquared or Fisher tests and logistic regression analysis. In 13 patients on enalapril treatment, a second ophthalmological evaluation was performed after a 12-month period to evaluate the longitudinal effect of the drug on ocular vessels. Results: Conjunctival vessel alteration (CVA) was not influenced by age, gender, HbF estimation, serum creatinine and albuminuria levels, GFR values, b-globin gene haplotypes or a-thalassaemia. However, increased frequencies of CVA were found in patients with Hb £ 9.0 g/dl, Ht £ 26.7% and sickle cell anaemia (SS) phenotype. Retinal vessel alteration (RVA) was identified only in patients aged 17 years or older. Enalapril did not demonstrate ocular vessel amelioration after 12-months of daily use. Conclusion:The results indicate that lower Hb and Ht levels and SS phenotype are risk factors for CVA, and age over 17 years may be risk factors for RVA in SCD patients.

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β^S‐gene‐cluster haplotypes in sickle cell anemia patients from two regions of Brazil

Cited by 24 publications

References 5 publications

Effects of hydroxyurea in a population of Brazilian patients with sickle cell anemia

Effects of hydroxyurea in a population of Brazilian patients with sickle cell anemia

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

Risk factors for conjunctival and retinal vessel alterations in sickle cell disease

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βS‐gene‐cluster haplotypes in sickle cell anemia patients from two regions of Brazil

Cited by 24 publications

References 5 publications

Effects of hydroxyurea in a population of Brazilian patients with sickle cell anemia

Effects of hydroxyurea in a population of Brazilian patients with sickle cell anemia

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

Risk factors for conjunctival and retinal vessel alterations in sickle cell disease

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β^S‐gene‐cluster haplotypes in sickle cell anemia patients from two regions of Brazil