Hemoglobinopathies and Sickle Cell Disease

Key Points Inherited hemoglobin disorders account for most common single-gene defect in humans.Thalassemias are caused by mutations in the globin gene cluster, resulting in a decrease in globin chain synthesis while structural hemoglobinopathies usually result from a point mutation in the α- or β-globin gene that causes a functional abnormality.High-performance liquid chromatography has become the test of choice for the diagnosis of thalassemias and hemoglobinopathies because it reliably separates different hemoglobins.Newborn screening has helped with early diagnosis and management, thus decreasing morbidity and improving longevity.Blood transfusion, and appropriate use of iron chelating agents are mainstay of the treatment. Use of appropriate antibiotic prophylaxis starting from the neonatal period and appropriate vaccinations have decreased morbidity and improved survival in patients with sickle cell disease.

Author(s):  
David Rees

Inherited abnormalities of the globin genes are the commonest single-gene disorders in the world and fall into two main groups: thalassaemias and sickle cell disease. Thalassaemias are due to quantitative defects in globin chain synthesis which cause variable anaemia and ineffective erythropoiesis. Thalassaemia was initially thought to be a disease of the bones due to uncontrolled bone marrow expansion causing bony distortion, although this is now unusual with appropriate blood transfusions. Osteopenia, often severe, is a feature of most patients with thalassaemia major and intermedia, caused by bone marrow expansion, iron overload, endocrinopathy, and iron chelation. Treatment with bisphosphonates is generally recommended. Other rheumatological manifestations include arthropathy associated with the use of the iron chelator deferiprone. Sickle cell disease involves a group of conditions caused by polymerization of the abnormal -globin chain, resulting in abnormal erythrocytes which cause vaso-occlusion, vasculopathy, and ischaemic tissue damage. The characteristic symptom is acute bone pain caused by vaso-occlusion; typical episodes require treatment with opiate analgesia and resolve spontaneously by 5 days with no lasting bone damage. The frequency of acute episodes varies widely between patients. The incidence of osteomyelitis is increased, particularly with salmonella, although it is much rarer than acute vaso-occlusion. Avascular necrosis can affect the hips, and less commonly the shoulders and knees. Coincidental rheumatological disease sometimes complicates the condition, particularly systemic lupus erythematosus (SLE) which is more prevalent in populations at increased risk of sickle cell disease.


Blood ◽  
1980 ◽  
Vol 56 (6) ◽  
pp. 1092-1099
Author(s):  
A Dubart ◽  
M Goossens ◽  
Y Beuzard ◽  
N Monplaisir ◽  
U Testa ◽  
...  

Isoelectric focusing (IEF) of hemoglobin was compared to the classical chromatography of labeled globin chains for 22 antenatal diagnoses of hemoglobinopathies: 11 for beta thalassemia, and 11 for sickle cell disease. In all cases, the two methods gave identical results. The diagnosis was confirmed after birth or abortion. Three fetuses homozygous for beta thalassemia and one homozygous for sickle cell disease exhibited no Hb A by IEF, in contrast to normal fetuses or those heterozygous for one of the two hemoglobinopathies. In addition, blood samples obtained in other centers after abortion of 22 fetuses homozygous for beta + or beta 0 thalassemia exhibited no Hb A when analyzed by IEF. When Hb A was present, the respective proportions of Hb A and acetylated Hb F were determined by densitometry of the IEF gel. The Hb A/acetylated Hb F ratio obtained by IEF correlated well with the beta A/gamma ratio of globin chain synthesis, IEF requires 0.1 mg of unlabeled hemoglobin. It is performed in 90 min and several samples can be analyzed simultaneously. If present, maternal contamination of fetal blood must be eliminated by selective lysis of maternal (RBC) using the Orskov reaction. Improvements in this method to obtain suitable samples for IEF analysis are described.


Blood ◽  
1980 ◽  
Vol 56 (6) ◽  
pp. 1092-1099 ◽  
Author(s):  
A Dubart ◽  
M Goossens ◽  
Y Beuzard ◽  
N Monplaisir ◽  
U Testa ◽  
...  

Abstract Isoelectric focusing (IEF) of hemoglobin was compared to the classical chromatography of labeled globin chains for 22 antenatal diagnoses of hemoglobinopathies: 11 for beta thalassemia, and 11 for sickle cell disease. In all cases, the two methods gave identical results. The diagnosis was confirmed after birth or abortion. Three fetuses homozygous for beta thalassemia and one homozygous for sickle cell disease exhibited no Hb A by IEF, in contrast to normal fetuses or those heterozygous for one of the two hemoglobinopathies. In addition, blood samples obtained in other centers after abortion of 22 fetuses homozygous for beta + or beta 0 thalassemia exhibited no Hb A when analyzed by IEF. When Hb A was present, the respective proportions of Hb A and acetylated Hb F were determined by densitometry of the IEF gel. The Hb A/acetylated Hb F ratio obtained by IEF correlated well with the beta A/gamma ratio of globin chain synthesis, IEF requires 0.1 mg of unlabeled hemoglobin. It is performed in 90 min and several samples can be analyzed simultaneously. If present, maternal contamination of fetal blood must be eliminated by selective lysis of maternal (RBC) using the Orskov reaction. Improvements in this method to obtain suitable samples for IEF analysis are described.


2011 ◽  
Vol 412 (13-14) ◽  
pp. 1257-1261 ◽  
Author(s):  
Philippe Joly ◽  
Philippe Lacan ◽  
Caroline Garcia ◽  
Angelique Delasaux ◽  
Alain Francina

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Huiqiao Chen ◽  
Zixuan Wang ◽  
Shanhe Yu ◽  
Xiao Han ◽  
Yun Deng ◽  
...  

AbstractThe human ζ-globin gene (HBZ) is transcribed in primitive erythroid cells only during the embryonic stages of development. Reactivation of this embryonic globin synthesis would likely alleviate symptoms both in α-thalassemia and sickle-cell disease. However, the molecular mechanisms controlling ζ-globin expression have remained largely undefined. Moreover, the pharmacologic agent capable of inducing ζ-globin production is currently unavailable. Here, we show that TRIAC, a bioactive thyroid hormone metabolite, significantly induced ζ-globin gene expression during zebrafish embryogenesis. The induction of ζ-globin expression by TRIAC was also observed in human K562 erythroleukemia cell line and primary erythroid cells. Thyroid hormone receptor α (THRA) deficiency abolished the ζ-globin-inducing effect of TRIAC. Furthermore, THRA could directly bind to the distal enhancer regulatory element to regulate ζ-globin expression. Our study provides the first evidence that TRIAC acts as a potent inducer of ζ-globin expression, which might serve as a new potential therapeutic option for patients with severe α-thalassemia or sickle-cell disease.


Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 296
Author(s):  
Rosa Vona ◽  
Nadia Maria Sposi ◽  
Lorenza Mattia ◽  
Lucrezia Gambardella ◽  
Elisabetta Straface ◽  
...  

Sickle cell disease (SCD) is the most common hereditary disorder of hemoglobin (Hb), which affects approximately a million people worldwide. It is characterized by a single nucleotide substitution in the β-globin gene, leading to the production of abnormal sickle hemoglobin (HbS) with multi-system consequences. HbS polymerization is the primary event in SCD. Repeated polymerization and depolymerization of Hb causes oxidative stress that plays a key role in the pathophysiology of hemolysis, vessel occlusion and the following organ damage in sickle cell patients. For this reason, reactive oxidizing species and the (end)-products of their oxidative reactions have been proposed as markers of both tissue pro-oxidant status and disease severity. Although more studies are needed to clarify their role, antioxidant agents have been shown to be effective in reducing pathological consequences of the disease by preventing oxidative damage in SCD, i.e., by decreasing the oxidant formation or repairing the induced damage. An improved understanding of oxidative stress will lead to targeted antioxidant therapies that should prevent or delay the development of organ complications in this patient population.


2004 ◽  
Vol 286 (4) ◽  
pp. L705-L714 ◽  
Author(s):  
Kirkwood A. Pritchard ◽  
Jingsong Ou ◽  
Zhijun Ou ◽  
Yang Shi ◽  
James P. Franciosi ◽  
...  

Vaso-occlusive events are the major source of morbidity and mortality in sickle cell disease (SCD); however, the pathogenic mechanisms driving these events remain unclear. Using hypoxia to induce pulmonary injury, we investigated mechanisms by which sickle hemoglobin increases susceptibility to lung injury in a murine model of SCD, where mice either exclusively express the human α/sickle β-globin (hαβS) transgene (SCD mice) or are heterozygous for the normal murine β-globin gene and express the hαβStransgene (mβ+/-, hαβS+/-; heterozygote SCD mice). Under normoxia, lungs from the SCD mice contained higher levels of xanthine oxidase (XO), nitrotyrosine, and cGMP than controls (C57BL/6 mice). Hypoxia increased XO and nitrotyrosine and decreased cGMP content in the lungs of all mice. After hypoxia, vascular congestion was increased in lungs with a greater content of XO and nitrotyrosine. Under normoxia, the association of heat shock protein 90 (HSP90) with endothelial nitric oxide synthase (eNOS) in lungs of SCD and heterozygote SCD mice was decreased compared with the levels of association in lungs of controls. Hypoxia further decreased association of HSP90 with eNOS in lungs of SCD and heterozygote SCD mice, but not in the control lungs. Pretreatment of rat pulmonary microvascular endothelial cells in vitro with xanthine/XO decreased A-23187-stimulated nitrite + nitrate production and HSP90 interactions with eNOS. These data support the hypotheses that hypoxia increases XO release from ischemic tissues and that the local increase in XO-induced oxidative stress can then inhibit HSP90 interactions with eNOS, decreasing ·NO generation and predisposing the lung to vaso-occlusion.


2021 ◽  
Author(s):  
Moataz Dowaidar

Autologous transplantation of gene-modified HSCs might be used to treat Sickle Cell Disease (SCD) once and for all. Hematopoietic Stem Cell (HSC) gene therapy with lentiviral-globin gene addition was optimized by HSC collection, vector constructs, lentiviral transduction, and conditioning in the current gene therapy experiment for SCD, resulting in higher gene marking and phenotypic correction. Further advancements over the next decade should allow for a widely approved gene-addition therapy. Long-term engraftment is crucial for gene-corrected CD34+ HSCs, which might be addressed in the coming years, and gene repair of the SCD mutation in the-globin gene can be achieved in vitro using genome editing in CD34+ cells. Because of breakthroughs in efficacy, safety, and delivery strategies, in vivo gene addition and gene correction in BM HSCs is advancing. Overall, further research is needed, but HSC-targeted gene addition/gene editing therapy is a promising SCD therapy with curative potential that might be widely available soon.


Author(s):  
Akaba Kingsley ◽  
Ofem Enang ◽  
Ofonime Essien ◽  
Annette Legogie ◽  
Omini Cletus ◽  
...  

Background: Sickle cell disease (SCD) is the commonest genetic disorder worldwide with a global prevalence of 20-25 million. About 12-15 million affected persons are in Sub-Sahara Africa with Nigeria bearing the highest burden of people living with sickle cell disease. SCD is a disease characterized as an autosomal, recessive, heterogeneous, and a monogenetic disorder caused by an A-to-T point mutation in the β-globin gene responsible for the production of abnormal hemoglobin S (HbS), which polymerizes in the deoxygenated state and results in the sickling of erythrocytes.  Haemoglobin variants are mutant forms of haemoglobin in a population usually occurring as a result of genetic changes in specific genes, or globins that causes change on alterations in the amino acid. They could affect the structure, behavior, the production rate and the stability of the specific gene. Well-known haemoglobin variants such as sick-cell anaemia are responsible for diseases and are considered haemoglobinopathies. Other variants cause no detectable pathology and are thus considered as non-pathological variants. Aim: The study is aimed at evaluating the burden of sickle cell disease and other haemoglobin variants in Calabar, South-South Nigeria. Methods: This is a retrospective study done at the haematology laboratory of University of Calabar Teaching Hospital, Calabar. Cellulose acetate electrophoresis at alkaline pH was used for the evaluation of haemoglobinopathies. The data were entered into Microsoft Excel 2016 spreadsheet and analysed with the IBM SPSS Version 22. Data were summarized into percentage of different phenotypes. Results: Results of the total 3648 haemoglobin electrophoresis recorded, 1368 (37.50%) were male while the remaining 2280 (62.5%) females given a male to female ratio of 1:1.7. Five haemoglobin phenotypes were identified as HbAA, HbAS, HbAC, HbSC and HbSS. The overall average values of their prevalence were HbAA 64.78%, HbAS 32.62%, HbSS 2.14%, HbAC 0.33%, HbSC 0.14%. Thus, the prevalence of SCD (Prevalence of HbSS+HbSC) was 2.28%. The highest proportion of SCD was observed in 2011 with least in 2016 and 2017 respectively. Conclusion: The prevalence of SCD and other haemoglobin variants in Calabar is similar to that of the national prevalence rate. There is need for continuous enlightenment and premarital counselling on the pattern of inheritance of SCD most especially with the increased burden of sickle traits in the environment has reported in this study.


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