*Beta thalassaemia in Nigeria: Myth or Fact?
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Background: The high prevalence of sickle cell disorders and the mild deletional α-thalassaemia among Nigerians is well known, but β-thalassaemia is believed to be almost nonexistent. Beta thalassaemia trait (BTT) was screened for in patients with unexplained recurrent haemolytic anaemia and healthy individuals.
Methods: β-thalassaemia trait (BTT) was screened for using MCH and HbA2 of 27pg and 3.5% respectively as cut off in 151 Nigerians which included 29 patients and 122 apparently healthy individuals. The subjects were categorized into four, Group I (high HbA2 , low MCH), Group II (low HbA2 and MCH), Group III (high HbA2 and high/normal MCH) and Group IV (normal HbA2 and MCH).
Results: Group I are possible carriers of BTT while group IV are least likely to carry either alpha or beta thalassaemia genes. There were 36 (26%), 39 (28%), 27 (19%) and 38 (27%) in groups I-IV respectively. The mean MCH, MCV, haematocrit and HbA2 for the study population were 26±2.8, 81±7.9, 37.5±6.8 and 3.4±1.7 respectively. The mean MCV and haematocrit were significantly lower for group I compared to group IV (76.9 Vs 86.6, p=0.00) and (36.5Vs39.7, p=0.03) respectively. Group II had significantly lower MCV and haematocrit than group IV (75.4(p=0.00) and 36.4(p=0.01) respectively. There was a positive correlation between the MCH and MCV with the haematocrit (p=0.004, p=0.001 respectively) but HbA2 showed a stronger negative correlation with the haematocrit (p<0.0001).
Conclusion: This does not only show the presence of BTT, but a higher prevalence than previously thought, mutations responsible for it should therefore be characterized.
Keywords: β-thalassaemia, red cell indices, haemoglobin, haemolytic anaemia
Résumé
Contexte: La prévalence élevée de la drépanocytose troubles et de mild deletional α-thalassémie entre Nigérians est bien connue, mais β-thalassémie est presque inexistant. Version bêta thalassémie attribut (TTC) a été projeté pour les patients avec récurrentes inexpliquées anémie hémolytique et individus en bonne santé.
Méthodes: une taxe a été projeté pour l’utilisation SMI et HBA2 de 27pg et 3,5 % respectivement, de couper de 151 Nigérians, qui comprenait 29 patients et 122 individus apparemment en bonne santé. Les sujets ont été répartis en quatre, le Groupe I (HbA2 élevée, faible SMI), Groupe II (faible HbA2 & SMI), du groupe III (haute HbA2 & haute/normal SMI) et du groupe IV (normal HbA2 & SMI).
Résultats: Groupe I sont possibles les transporteurs de la TOC tandis que le groupe IV sont moins susceptibles de transporter alpha ou bêta thalassémie gènes. Il y a eu 36 (26%), 39 (28%), 27 (19%) et 38 (27%) dans les groupes I-IV, respectivement. La moyenne SMI, MCV, hématocrite et HBA2 pour la population de l’étude était de 26 ± 2,8 , 81 ± 7,9 , 37,5 ± 6,8 et 3,4 ± 1,7 respectivement. Les MCV et hématocrite étaient sensiblement inférieurs pour le groupe I par rapport au groupe IV (76,9 vs 86,6 , p=0.00 ) et ( 36,5 Vs39.7, p=0.03 ) respectivement. Groupe de travail II avait sensiblement inférieur MCV et de l’hématocrite de groupe IV (75,4 (p=0.00 ) et 36,4 (p=0.01 ) respectivement. Il y avait une corrélation positive entre la santé maternelle et infantile et MCV avec l’ hématocrite (p=0.004 , p=0.001 respectivement) mais HbA2 a montré une forte corrélation négative avec l’hématocrite (p < 0,0001 ).
Conclusion: Ce n’est pas seulement montrer la présence de la TOC, mais une prévalence plus élevée qu’on ne le pensait auparavant, des mutations responsables devraient donc être caractérisée.
Correspondence: Dr. T.R. Kotila, Department of Haematology, College of Medicine, University of Ibadan, Ibadan, Nigeria. E-mail: tkotila@comui.edu.ng
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