Disorders of the synthesis or function of haemoglobin

2020 ◽  
pp. 5426-5450
Author(s):  
Deborah Hay ◽  
David J. Weatherall

The inherited disorders of haemoglobin are the commonest single-gene disorders in the world. Disorders of haemoglobin can be genetic or acquired and due to disordered production of one or more globin chains or structural change in the globin chain. The most important disorders are the genetic conditions thalassaemia and sickle cell disease. Thalassaemia—a heterogeneous group of genetic disorders, all resulting from a reduced rate of production of one or more of the globin chains of haemoglobin and inherited in a simple Mendelian fashion. They are clinically classified according to their severity into major (a severe transfusion-dependent disorder), intermediate (characterized by anaemia and splenomegaly), and minor (a symptomless carrier state) forms. The β‎ thalassaemias are the most important types of thalassaemia because they are very common and produce severe anaemia in their homozygous and compound heterozygous states. Most countries in which the disease is common are putting a major effort into programmes for its prevention (population screening and prenatal diagnosis). Symptomatic management of severe disease requires regular blood transfusion, judicious use of splenectomy if hypersplenism develops, and chelating agents to reduce iron overload. Sickle cell disease—haemoglobin S differs from haemoglobin A by the substitution of valine for glutamic acid at position 6 in the β‎ globin chain, and homozygosity for haemoglobin S produces the state of sickle cell disease. This occurs very frequently in African populations and, sporadically, throughout the Mediterranean region and the Middle East, with extensive pockets in India. Management of both acute and chronic complications remains largely supportive, with hydroxycarbamide being the only clinically proven effective treatment to date.

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.


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.


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 ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3235-3235
Author(s):  
Despoina Adamidou ◽  
Erasmia Rouka ◽  
Despoina Kyriakou ◽  
Stamatia Theodoridou ◽  
E Vetsiou ◽  
...  

Abstract Abstract 3235 Endothelial damage is one of the major mechanisms causing most of the manifestations in sickle cell disease (SCD). We hypothesized that a possible defect in the cleavage of large vWF multimers through the protease ADAMTS13 could add further to the well established chronic activation of the endothelium and consequently to the severity of the disease. For this purpose we measured the activity of the enzyme and looked for any correlations with regard to the clinical phenotype of patients with SCD. We studied 22 steady state patients (9 men/13 women) with a median age of 35(22–74) years. Of them, 3 were in homozygous state(HbSS) and 19 were compound heterozygous for thalassamia β(HbS/β+, HbS/β0). The clinical phenotype was mild in 12 patients, moderate in 3 and 7 were suffering from severe symptoms (history of frequent vaso-occlusive and acute chest crises and need for regular exchange transfusion). We applied FRET (fluorescence resonance energy transfer) technique to measure ADAMTS13 activity (normal values>65%). Factor VIII and vWF: Ag was measured using 1-stage clotting assay and immunoassay respectively (normal values 50–150%). We considered all relevant clinical parameters (spleen size, transfusion frequency, comorbidities, and medications with special regard to iron chelation, hydroxyurea and antiplatelet agents) together with laboratory readings (markers of haemolysis, proportion of haemoglobin fractions using high-performance liquid chromatography HPLC).We used as control group 22 healthy volunteers blood donors with their written consent matched for age, sex, body mass index and ABO blood group. All samples were taken at least 30 days post last transfusion. We found higher levels of both vWF: Ag [189(33–345)] and ADAMTS13 [164(75–310)] in the patients compared to the control group [87(44–152) και 126(55–171) (p<0.001/p<0.025)] respectively. When we analyzed the ratio ADAMTS13/vWF: Ag we found significant difference between the two groups: 1,041(0.3–4.6) vs 1.56(0.5–2.6) (p<0.020). Furthermore, patients with severe disease experienced significantly lower ratio ADAMTS/vWF 0.7(0.5–1.2) compared to both control group (p<0.001) as well as patients with milder clinical phenotype [1.30(0.3–4.6)].Of note, in patients with severe SCD despite the fact that vWF: Ag levels were found considerably higher and in significant difference with the control group [196(130–345) vs 87(44–152)p<0.001], we could not find the same pattern for ADAMTS13 [140(75–210) vs 126(55–171)].The lower ratio found in patients with SCD and in particular in those with severe disease might indicate the need for higher protease levels in comparison to healthy controls. It looks like in this group of patients ADAMTS13, although normal, is not sufficient enough to manage the reasonably high vWF levels that characterize the chronic endothelial activation. This relevant deficiency of the metaloprotease might be caused by either biggest consumption due to large and constant release of its substrate-vWF or by an acquired inhibition of its action as the free intravascular hemoglobin might exhibit an antagonistic role for the binding site of vWF. In conclusion, the low ADAMTS13/vWF: Ag ratio seems to detect patients with severe SCD and would be of interest to prospectively investigate its role both as a prognostic tool as well as a potential therapeutic target. Disclosures: No relevant conflicts of interest to declare.


2002 ◽  
Vol 2 ◽  
pp. 1706-1728 ◽  
Author(s):  
Martin H. Steinberg

High fetal hemoglobin (HbF) levels inhibit the polymerization of sickle hemoglobin (HbS) and reduce the complications of sickle cell disease. Pharmacologic agents that can reverse the switch from γ- to β-chain synthesis — γ-globin chains characterize HbF, and sickle β-globin chains are present in HbS — or selectively increase the proportion of adult erythroid precursors that maintain the ability to produce HbF are therapeutically useful. Hydroxyurea promotes HbF production by perturbing the maturation of erythroid precursors. This treatment increases the total hemoglobin concentration, reduces the vaso-occlusive complications of pain and acute chest syndrome, and attenuates mortality in adults. It is a promising beginning for pharmacologic therapy of sickle cell disease. Still, its effects are inconsistent, trials in infants and children are ongoing, and its ultimate value — and peril — when started early in life are still unknown.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 20-20
Author(s):  
Victoria Brooks ◽  
Oluwalonimi Adebowale ◽  
Victor R. Gordeuk ◽  
Sergei Nekhai ◽  
James G. Taylor

Background: Blood transfusion is a common therapy for sickle cell disease (SCD). Although, highly effective, a major limitation is development of alloantibodies to minor blood group antigens on donor red cells. Alloimmunization has a prevalence of 2-5% for transfusions in the general population, but it is significantly higher in SCD. Risk factors for alloimmunization have been poorly characterized, although number of lifetime transfusions is an important risk factor. Alloimmunization has been clinically observed in children with a prevalence of about 7%. With development of each antibody, blood donor matching becomes increasingly difficult and expensive with an increased risk for transfusion reactions and diminished availability of compatible red cell units for treatment of SCD. The ability to identify risk factors for developing alloantibodies would be beneficial for clinicians. To identify markers for alloimmunization in SCD, we have analyzed children and adults who developed this complication. Methods: We analyzed The Pulmonary Hypertension and Hypoxic Response in Sickle Cell Disease (PUSH) study, which enrolled n=468 pediatric and n=59 adult SCD subjects. In both children and adults, alloimmunization cases were defined as a history of at least 1 alloantibody. Controls in both cohorts were defined as subjects with no history of alloantibodies and receipt of more than 10 lifetime red cell transfusions. All others within the study who did not meet these criteria were assigned to a third comparison group. To identify differences between cases, controls and all others, we performed univariate analyses (using ANOVA or Kruskal Wallace where appropriate) for clinical parameters and laboratories. Case control comparisons were also performed for selected variables and plasma levels for 11 cytokines. Results were further analyzed using regression modeling. Results: The overall prevalence of alloimmunization was 7.3% among children (34/468 subjects; median age 12, range 3-20 years) compared to 28.8% in adults (17/59 subjects; median age 37, range 18-73 years). When only considering those with &gt;10 lifetime transfusions, the prevalence was considerably higher at 29.3% and 54.8% in children and adults, respectively. At the same time, 8 pediatric (23.5%) and 5 adult (29.4%) alloimmunization cases had received fewer than 10 transfusions. In a 3-way pediatric cohort comparison (cases, controls and all others), risk factors associated with alloimmunization included SS genotype, older age and markers of more severe disease (higher ferritin, WBCs, platelets and total bilirubin). Comparison of cases to controls showed alkaline phosphatase (P=0.05) was significantly lower in cases, whereas AST (P=0.02) was significantly higher even with adjustment for age. Levels of plasma cytokines MCP-1 (P=0.01) and IFNgamma (P=0.08) were lower in cases from a subset of the pediatric cohort. In adults, only 4/59 (6.8%) subjects had never received a lifetime transfusion (all non-SS). In the adult 3-way comparisons, only SS genotype and higher ferritin were associated with alloimmunization. The adult case control analysis showed higher absolute monocyte count (P=0.02), absolute eosinophil count (P=0.04) and absolute basophil count (P=0.008) in association with alloimmunization cases. In addition, alkaline phosphatase was again significantly lower among cases (P=0.02) as seen in the pediatric cohort. There were no significant differences in cytokine levels among adults. Conclusions: When considering only transfused SCD patients, the prevalence of alloimmunization is higher than 30%. As seen in prior studies, higher lifetime red cell transfusions are an important risk factor especially among adults where most patients have received transfusions. Children who develop alloantibodies appear to have laboratory markers of more severe disease, but this is not observed in adults. A novel association observed across both pediatric and adult subjects is a significantly lower serum alkaline phosphatase in those with alloantibodies. The results of this study suggest a need for improved tracking of red cell transfusion therapy in the US for SCD patients due to a high prevalence of alloimmunization. Further study is also needed to elucidate the significance of the alkaline phosphatase association. Disclosures Gordeuk: CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Novartis: Consultancy; Ironwood: Research Funding; Imara: Research Funding.


2016 ◽  
Vol 113 (38) ◽  
pp. 10661-10665 ◽  
Author(s):  
Lin Ye ◽  
Jiaming Wang ◽  
Yuting Tan ◽  
Ashley I. Beyer ◽  
Fei Xie ◽  
...  

Hereditary persistence of fetal hemoglobin (HPFH) is a condition in some individuals who have a high level of fetal hemoglobin throughout life. Individuals with compound heterozygous β-thalassemia or sickle cell disease (SCD) and HPFH have milder clinical manifestations. Using RNA-guided clustered regularly interspaced short palindromic repeats-associated Cas9 (CRISPR-Cas9) genome-editing technology, we deleted, in normal hematopoietic stem and progenitor cells (HSPCs), 13 kb of the β-globin locus to mimic the naturally occurring Sicilian HPFH mutation. The efficiency of targeting deletion reached 31% in cells with the delivery of both upstream and downstream breakpoint guide RNA (gRNA)-guided Staphylococcus aureus Cas9 nuclease (SaCas9). The erythroid colonies differentiated from HSPCs with HPFH deletion showed significantly higher γ-globin gene expression compared with the colonies without deletion. By T7 endonuclease 1 assay, we did not detect any off-target effects in the colonies with deletion. We propose that this strategy of using nonhomologous end joining (NHEJ) to modify the genome may provide an efficient approach toward the development of a safe autologous transplantation for patients with homozygous β-thalassemia and SCD.


Blood ◽  
1996 ◽  
Vol 87 (3) ◽  
pp. 887-892 ◽  
Author(s):  
S Fucharoen ◽  
N Siritanaratkul ◽  
P Winichagoon ◽  
J Chowthaworn ◽  
W Siriboon ◽  
...  

Hydroxyurea (HU) is one of several agents that have been shown to enhance hemoglobin (Hb) F levels in patients with sickle cell disease and may be useful as a therapy for beta-globinopathies. However, limited information exists on the effects of HU in patients with thalassemia. Accordingly, we examined the hematologic effects of orally administered HU in 13 patients with beta-thalassemia/Hb E, including four patients who had been splenectomized. These patients were treated with escalating doses (final range, 10 to 20 mg/kg/d) for 5 months and were observed in the outpatient hematology clinic every 2 to 4 weeks. Complete blood counts including reticulocyte counts, amounts of Hb E and Hb F, G gamma:A gamma and alpha:non-alpha globin biosynthetic ratios were evaluated before and during treatment. Almost all patients responded with an average increase of 33% in Hb F levels, from a mean (+/- SD) of 42% +/- 11% to 56% +/- 8% (P < .0001), and a reciprocal decline in the percentage of Hb E from 59% +/- 9% to 49% +/- 8% (P < .001). Reticulocytosis was decreased from a mean (+/- SD) of 18.0% +/- 15.6% to 11.7% +/- 9.1% (P < .05); there was also a slight (10%) but statistically significant increase in hemoglobin levels and an improved balance in alpha:non-alpha globin chains ratios. The side effects were minimal in most patients, although these patients tended to tolerate a lower dose of HU before significant myelosuppression than has been our previous experience in sickle cell disease. One splenectomized patient died of sepsis during the trial. We conclude that increased Hb F production in beta-thalassemia/Hb E patients, with an improvement in the alpha:non-alpha globin ratios and, probably, the effectiveness of erythropoiesis, can be achieved using HU. Longer trials of HU in this population, including at other doses and in combination with other agents, appear warranted.


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