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1.
Acta Haematol ; 142(3): 132-141, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31352439

RESUMO

Thalassaemias are the most common inherited autosomal recessive single gene disorders characterised by chronic hereditary haemolytic anaemia due to absence or reduced synthesis of one or more of the globin chains. Haemoglobin E (HbE)-ß-thalassaemia is the genotype responsible for approximately one-half of all cases of severe ß-thalassaemia worldwide. This study proposes to evaluate response of hydroxyurea in reducing transfusion requirements of severe HbE-ß-thalassaemia patients, and its correlation with foetal haemoglobin (HbF) level and α-mutation. Hydroxyurea was started at a baseline dose in 82 transfusion-dependent HbE-ß-thalassaemia patients. HbF levels and %F-cells were measured. ß-Thalassaemia mutations and α-globin gene deletions and triplications were detected by amplification refractory mutation system (ARMS)-polymerase chain reaction (PCR) and Gap-PCR, respectively. Patients were categorised as good (41.5%), moderate (31.7%), and poor responders (26.8%) based on their decrease in transfusion requirements. Nine patients were excellent responders who became transfusion independent. The mean increase in HbF levels and %F-cells after therapy was correlated with decrease in transfusion requirements. Patients having a deletion of the α-globin gene were better responders. The response was proportional to the number of α-globin gene deletions. We conclude that hydroxyurea treatment decreases transfusion requirements, and the response correlates with α-globin gene deletions.

2.
Ann Hematol ; 98(8): 1827-1834, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31190133

RESUMO

In this study, we aimed to investigate the pattern and association of genetic mutations occurring within the alpha hemoglobin-stabilizing protein (AHSP) gene among HbE beta thalassemia patients with varying phenotypic expressions. Fifty-four diagnosed cases of HbE beta thalassemia (transfusion dependent and independent) were included in the study. Among them, 38 patients with similar genotypes (IVS 1-5, alpha gene deletion and triplication, Xmn polymorphism) were selected for further analysis. AHSP gene sequencing was done for these 38 samples to study associated mutations in AHSP gene. HbE beta thalassemia patients with similar genotypes but different phenotypic expressions were found to have mutations in the AHSP gene. There were five mutations found most prevalent among the samples analyzed for AHSP gene sequencing. Among these, two mutations were from intron 1 region of AHSP and three mutations were found in exon 3. The most prevalent mutation was found at the Oct binding site at intron 1 of AHSP. The mutations in exon 3 were more prevalent among the TDT groups. A mutation in exon 3 changing the amino acid (33rd) from serine to phenylalanine was found to be associated with only TDT group. This study documents that among the HbE beta thalassemia patients with varying severity, an exon mutation in AHSP is significantly prevalent only among the TDT group. Further understanding of the mechanism will shed light upon the impact of AHSP in modifying the disease severity in thalassemia.


Assuntos
Proteínas Sanguíneas/genética , Deleção de Genes , Duplicação Gênica , Hemoglobina E/genética , Chaperonas Moleculares/genética , Talassemia beta/genética , Adolescente , Adulto , Sequência de Bases , Proteínas Sanguíneas/metabolismo , Transfusão de Sangue/estatística & dados numéricos , Criança , Pré-Escolar , Análise Mutacional de DNA , Eritrócitos/metabolismo , Eritrócitos/patologia , Éxons , Feminino , Expressão Gênica , Genótipo , Hemoglobina E/metabolismo , Humanos , Íntrons , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Chaperonas Moleculares/metabolismo , Fenótipo , Estrutura Secundária de Proteína , Índice de Gravidade de Doença , Talassemia beta/metabolismo , Talassemia beta/patologia , Talassemia beta/terapia
3.
Ann Hematol ; 98(2): 289-299, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30413899

RESUMO

Thalassaemia are the most common inherited autosomal recessive single gene disorders characterized by chronic hereditary haemolytic anaemia due to the absence or reduced synthesis of one or more of the globin chains. Haemoglobin E-ß thalassaemia is the genotype responsible for approximately one half of all severe beta-thalassaemia worldwide. This study proposes to evaluate the effect of various molecular parameters on the response of hydroxyurea. Hydroxyurea was started at an initial dose of 10 mg/kg of body weight/day on 110 transfusion-dependent HbE-ß thalassaemia patients. HbF level was measured by HPLC analysis. ß-Thalassaemia mutations, XmnI and five other SNPs, and α-globin gene deletions and triplications were detected by ARMS-PCR, RFLP-PCR and Gap-PCR, respectively. Based on the factors for evaluating hydroxyurea-response, 42 patients were responders as they showed an increment of Hb from a mean baseline value of 6.45 g/dl (± 0.70) to 7.78 g/dl (± 0.72) post-therapy. Based on increase in HbF above the median value (14.72%) post-therapy, 78 patients were found to be responders. All the 78 responders showed mean decrease in transfusion of 74.26% (± 8.32) with a maximum decrease of 98.43%. There was a significant correlation between decrease in transfusion and increase in HbF level for all 78 responders. XmnI polymorphism showed the strongest association (p < 0.0001) with increase in HbF levels and Hb levels. Patients with α-globin gene deletions were better responders. It was concluded that hydroxyurea treatment is effective in transfusion-dependent HbE-ß thalassaemia patients and the response is best in patients having both XmnI polymorphism and α-deletion.


Assuntos
Transfusão de Sangue , Hemoglobina Fetal/biossíntese , Hemoglobina E/metabolismo , Hidroxiureia/administração & dosagem , Mutação , Polimorfismo de Nucleotídeo Único , Talassemia beta , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Hemoglobina Fetal/genética , Hemoglobina E/genética , Humanos , Masculino , Talassemia beta/sangue , Talassemia beta/genética , Talassemia beta/terapia
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