Hemoglobin SE disease: a concise review

Clinico-Hematological Profile in Hemoglobin SE Disease: A Case Series from a Tertiary Care Centre

Hemoglobin SE (HbSE) disease are rare globally and there is paucity of literature regarding this condition. Cases reported in the Indian scenario so far have been limited to the tribal populations. This case series aims to highlight the rarity of this double heterozygous state and to raise awareness of its community prevalence beyond the tribal population. This is a case series over a 5-year observation period with six cases of double heterozygosity for HbS and HbE in our tertiary care centre. Four cases were in the 8-15 years' age group and 2 cases of 24-25 years' age group reported for initial evaluation due to easy fatigability and weakness: Two cases were siblings with history of consanguineous marriages in the family. Mild Pallor, variable icterus, spleen was just palpable in three of the cases and low MCV recorded in all cases. Sickling tests were positive and high performance liquid chromatography (HPLC) revealed both HbS > 50% and HbE fractions ≥ 25%. It's important to detect this rare condition, prevalent in consanguineous marriages as dreaded complications like sickling crisis may manifest during pregnancy and air travel. Detection and genetic counselling is important for prognosis, planning follow up and therapy for this uncommon double heterozygous state.

Profiling of 35 Cases of Hb S/Hb E (HBB: c.20A>T/HBB: c.79G>a), Disease and Association with α-Thalassemia and β-Globin Gene Cluster Haplotypes from Odisha, India

Hb S/Hb E (HBB: c.20A>T/HBB: c.79G>A) is an uncommon variant of sickle cell disease resulting from coinheritance of Hb S and Hb E. Clinico-hematological and biochemical parameters of 35 cases of Hb S/Hb E disease were studied and compared with 70 matched cases of homozygous sickle cell disease (Hb SS) and Hb S/β-thalassemia (β-thal) with IVS-I-5 (G>C) (HBB: c.92+5G>C). The influence of α-thal and that of of β-globin gene cluster haplotypes among Hb S/Hb E disease was also studied. Statistical analysis was done using GraphPad InStat version 3.06. Of the 35 cases, 20 (57.14%) had a moderate clinical presentation. Mean lactate dehydrogenase (LDH) level, vaso-occlusive crises (VOCs) per year, and annual blood transfusion requirements were significantly lower in Hb S/Hb E cases than in the other two groups. The hemoglobin (Hb) and packed cell volume (PCV) levels were significantly high in Hb S/Hb E cases with α-thal and these cases were associated with microcytic-hypochromic anemia. α-Thalassemia did not influence clinical presentation in Hb S/Hb E cases. The β-globin gene cluster haplotypes of 70 alleles of Hb S/Hb E revealed an association of five typical haplotypes [Arab-Indian (A-I), Benin, Bantu, Cameroon and Senegal] in 95.71% cases. Hb S/Hb E disease exhibit asymptomatic to moderate phenotypic expression. However, further in-depth studies on Hb S/Hb E will help in reducing the disease burden especially in high-risk countries like India.

Acute chest syndrome in sickle cell disease/HBE patient, A case report

The presented case will shed some light on one of the rarest complications of HBSE disease, which is acute chest syndrome, and will highlight the management of that complication.

Manifestations of HbSE sickle cell disease: a systematic review

BACKGROUND

Sickle cell disease (SCD) is commonly encountered in Africa and Middle Eastern countries. The causative mutation in the gene encoding the hemoglobin subunit β (HBB) leads to various genotypic variants of the disease. This results in varied phenotypes, with a spectrum of complications, from benign to fatal. Hemoglobin SS (HBSS) genotype is associated with most of these complications; hence, it is a severe form of SCD. On the other hand, rare genotypes such as hemoglobin SE (HBSE) are considered benign. There is limited literature about the clinical manifestations and characteristics of patients with HBSE. We pooled all available data describing the phenotypic manifestations of HBSE heterozygote worldwide to perform a systematic review.

METHODS

We performed a systematic review according to PRISMA guidelines using PubMed, SCOPUS, and Google Scholar databases. Two independent reviewers (FA and IK) evaluated studies for eligibility and extracted data. We synthesized data on demographics, manifestations, and management of HBSE disease. PROSPERO Registration Number: CRD42021229877.

RESULTS

We found 68 HBSE patients reported in the literature. 24 cases were extracted from case reports whereas 44 cases from case series and retrospective studies. Turkey reported the highest number of patients (n = 22). 32 (47%) of the patients were males. The mean age was 20.9 ± 18.26 years. The mean HBS and HBE percentages were 61.1% ± 7.25% and 32.3% ± 5.06%, respectively, whereas the mean hemoglobin was 11.64 ± 1.73 g/dl. Reported manifestations of HBSE disease included acute vaso-occlusive pain crisis (n = 22, 32.3%), splenomegaly (n = 11, 16.1%), hemolytic anemia (n = 10, 14.7%), infections (n = 8. 11.7%), bone infarction (n = 4, 5.8%), gallstones (n = 3, 4.4%), venous thromboembolism (VTE) (n = 2, 2.9%) and stroke (n = 2, 2.9%), and hematuria (n = 2, 2.9%). Death due to HBSE complications was reported in three patients.

CONCLUSION

HBSE is a rare genotypic variant of SCD. It has been considered a benign form; however, there are multiple reports of severe complications. Severe complications observed in HBSE disease include vaso-occlusive crisis, acute chest syndrome, stroke, bone marrow embolism, and death.

OCCURRENCE OF UNUSUAL HAEMOGLOBINOPATHIES IN BALOCHISTAN: HB SD AND HB SE - PRESENTATION WITH OSTEOMYELITIS

OBJECTIVE

To describe two cases of unusual variants of sickle cell disease.

CASE DESCRIPTION

We present two cases of sickle cell disease variants (haemoglobinopathies), from unrelated families, in the state of Balochistan (Pakistan). One was diagnosed with sickle cell disease in the haemoglobin electrophoresis, whereas the other was diagnosed with sickle cell SE disease. Both were diagnosed based on the presentation of osteomyelitis.

COMMENTS

Haemoglobin SD disease (Hb SD) and haemoglobin SE disease (Hb SE) are rare haemoglobinopathies in the world. The lack of available literature suggests that both are variants of sickle cell disease (SCD), with heterogeneous nature. The prevalence of sickle cell disease with compound heterozygotes was found at a variable frequency in the population of the Asian Southeast. The frequency of osteomyelitis in SCD is 12 to 18%, but its occurrence among variant haemoglobinopathies is little reported. Both reported cases presented with osteomyelitis as a characteristic of the disease presentation.

Hemoglobin SE Disease Presenting as a High-Altitude Massive Splenic Infarction Complicated by Hemorrhagic Conversion and Splenectomy

Hemoglobin SE (HbSE) disease is a hemoglobinopathy resulting from the combination of hemoglobin S (HbS) and hemoglobin E (HbE) genotypes. It may present as a vaso-occlusive crisis (VOC) in the setting of an acute stressor. Herein, we present a case of undiagnosed HbSE disease presenting as a massive splenic infarct in the setting of high-altitude exposure. A 55-year-old female of South Asian descent presented with acute left upper quadrant abdominal pain after hiking in the Swiss Alps four days previously. Laboratory testing revealed that she had hemolytic anemia, and computed tomography (CT) imaging showed a greater than 50% splenic infarction. After the initiation of anticoagulation, she experienced a hemorrhagic conversion of the initial splenic infarct resulting in acute hemodynamic decompensation. She initially underwent vascular intervention with arterial plugging, coiling, and embolization but ultimately required a splenectomy and partial colectomy upon developing a large splenic hematoma. Hemoglobin electrophoresis was consistent with hemoglobin SE disease. Hemoglobin variants, especially combined heterozygosity, are rare and have the potential to present as a vaso-occlusive crisis in the setting of acute chemical and physiological stresses. Only 43 cases of hemoglobin SE disease have been previously reported and one other occurrence in the setting of high altitude. Conservative management is recommended when a diagnosis of sickle cell trait (SCT) is definite, in comparison with cardioembolic phenomena, in which antiplatelet and anticoagulant therapy should be initiated. Hemoglobin SE disease is a rare heterozygous hemoglobinopathy resulting from the combination of hemoglobin variants geographically separated by thousands of miles. Currently, there are no strict guidelines supporting anticoagulation for the management of VOC in hemoglobinopathies. Splenic infarct in HbSE disease should be managed similarly to SCT/sickle cell disease (SCD) with fluids and analgesia, and anticoagulation should be limited to confirmed thromboembolic events and with the insight of an anticoagulant specialist.

Paper-based microchip electrophoresis for point-of-care hemoglobin testing

Nearly 7% of the world's population live with a hemoglobin variant. Hemoglobins S, C, and E are the most common and significant hemoglobin variants worldwide. Sickle cell disease, caused by hemoglobin S, is highly prevalent in sub-Saharan Africa and in tribal populations of Central India. Hemoglobin C is common in West Africa, and hemoglobin E is common in Southeast Asia. Screening for significant hemoglobin disorders is not currently feasible in many low-income countries with the high disease burden. Lack of early diagnosis leads to preventable high morbidity and mortality in children born with hemoglobin variants in low-resource settings. Here, we describe HemeChip, the first miniaturized, paper-based, microchip electrophoresis platform for identifying the most common hemoglobin variants easily and affordably at the point-of-care in low-resource settings. HemeChip test works with a drop of blood. HemeChip system guides the user step-by-step through the test procedure with animated on-screen instructions. Hemoglobin identification and quantification is automatically performed, and hemoglobin types and percentages are displayed in an easily understandable, objective way. We show the feasibility and high accuracy of HemeChip via testing 768 subjects by clinical sites in the United States, Central India, sub-Saharan Africa, and Southeast Asia. Validation studies include hemoglobin E testing in Bangkok, Thailand, and hemoglobin S testing in Chhattisgarh, India, and in Kano, Nigeria, where the sickle cell disease burden is the highest in the world. Tests were performed by local users, including healthcare workers and clinical laboratory personnel. Study design, methods, and results are presented according to the Standards for Reporting Diagnostic Accuracy (STARD). HemeChip correctly identified all subjects with hemoglobin S, C, and E variants with 100% sensitivity, and displayed an overall diagnostic accuracy of 98.4% in comparison to reference standard methods. HemeChip is a versatile, mass-producible microchip electrophoresis platform that addresses a major unmet need of decentralized hemoglobin analysis in resource-limited settings.

Genetic Basis and Genetic Modifiers of β-Thalassemia and Sickle Cell Disease

β-thalassemia and sickle cell disease (SCD) are prototypical Mendelian single gene disorders, both caused by mutations affecting the adult β-globin gene. Despite the apparent genetic simplicity, both disorders display a remarkable spectrum of phenotypic severity and share two major genetic modifiers-α-globin genotype and innate ability to produce fetal hemoglobin (HbF, α₂γ₂).This article provides an overview of the genetic basis for SCD and β-thalassemia, and genetic modifiers identified through phenotype correlation studies. Identification of the genetic variants modifying HbF production in combination with α-globin genotype provide some prediction of disease severity for β-thalassemia and SCD but generation of a personalized genetic risk score to inform prognosis and guide management requires a larger panel of genetic modifiers yet to be discovered.Nonetheless, genetic studies have been successful in characterizing some of the key variants and pathways involved in HbF regulation, providing new therapeutic targets for HbF reactivation.

Unrecognized hemoglobin SE disease as microcytosis

Hemoglobin SE disease was first described during the 1950s as a relatively benign microcytosis, but increasing prevalence has revealed a predisposition towards vasoocclusive sickling. Recognition of SE hemoglobinopathies' potential complications is crucial so medical measures can be utilized to avoid multiorgan injury.

Hemoglobin SE Disease in Hatay, in the Southern Part of Turkey

Double heterozygosity for hemoglobin (Hb) E and S, known as HbSE disease, is a rare, clinically benign condition involving mild hemolysis. Only 25 cases have been reported to date. The current literature generally associates HbSE with a benign clinical course, although vaso-occlusive complications have been reported. Although only single case reports were previously available, we have observed 20 cases of HbSE and wish to report them. We examined the records of patients presenting to our hemoglobinopathy center in 2001–2013. High performance liquid chromatography (HPLC) was used for hematological assessment of blood samples with ethylenediaminetetraacetic acid. Eight patients were male and 12 female. Mean hemoglobin electrophoresis values were Hb A1: 6.3%, Hb E 34.5%, HbS: 59.5% and Hb F: 1.9%. Three patients (15%) were symptomatic with vaso-occlusive crisis and one had cerebral stroke. These were siblings. The patient with cerebral stroke was using hydroxyurea. The incidence of HbSE disease is rising due to population admixtures and racial intermarriages. Increased numbers of cases of HbSE have been detected after premarital hemoglobinopathy screening in the Antakya and Çukurova regions of Turkey. The aim of this study was to report large numbers of patients with HbSE diagnosed through the routine HPLC method. The secondary aim was to emphasize that severe vaso-occlusive crisis such as infarction symptoms could be seen in HbSE. E，S型双杂合性血红蛋白，被称为HbSE症，是一种罕见的，临床上呈良性的病症，通常伴有轻度溶血症状。迄今为止只有25个关于此病症的报告。当前通常把HbSE症是作为一种良性病患，尽管已有报告显示出其梗塞并发症的存在。虽然只有极少的相关报告，我们仍研究了20个HbSE病例，并希望能陈述我们的发现。 我们检查了2001–2013年患者在我们血红蛋白病中心提交的检测记录。高效液相色谱法（HPLC）及乙二胺四乙酸被采用以评估收集到的血液样本。患者为8名男性，12名女性。他们的平均血红蛋白电泳值分别为Hb A1: 6.3%、Hb E:34.5%、Hb S:59.5%,Hb F:1.9%。其中3位（15%）患者患有梗塞的并发症，一位患有脑卒中。这三名患者是兄弟姐妹。患有脑卒中的患者当时使用过羟基脲。HbSE症发病率的上升是由于人口及人种间的混血。在土耳其Antakya 和Çukurova 地区的婚前血红蛋白病的筛查中，发现了HbSE症病例的增加。该研究的目的是报告大量通过高效液相色谱法诊断的HbSE症病例。次要目的是强调例如梗塞的严重并发症会由HbSE症引发。

First Reported Case of Proliferative Retinopathy in Hemoglobin SE Disease

We report the first case of proliferative sickle cell retinopathy in a patient with hemoglobin SE (Hb SE) disease. Only a few dozen cases of Hb SE disease have been reported previously, and none had evidence of proliferative retinopathy. A 56-year-old African American man presented to our clinic for routine examination and was found to have sea-fan peripheral neovascularization bilaterally without maculopathy. Hemoglobin analysis revealed Hb SE heterozygosity. Sector laser photocoagulation to areas of nonperfusion in both eyes resulted in regression of the peripheral neovascularization over a period of 6 months. Although Hb SE disease is rare, the incidence of Hb SE disease is postulated to rise in the future. Awareness of its potential ocular complications is needed to appropriately refer these patients for screening.

Back pain: the sole of presentation of sickle cell disease

Diagnosing back pain in children and adolescents can be a challenge to health care providers. Although studies show that more than half of the cases of back pain in children are of non-organic cause, missing the right diagnosis could be detrimental. We present a case of lower back pain in a ten-year-old male whom we eventually diagnosed with hemoglobin SE mutation, which responded well to pain management. Hence, sickle cell disease with vaso-occlusive crisis should be incorporated into the list of differential diagnoses in children with back pain.

Sudden death after exercise in an adolescent with hemoglobin SE

Hemoglobin (Hb) S and Hb E are the most common variant hemoglobins, but because of the geographical separation of the areas where they are prevalent, the combination of the 2 is uncommon. Approximately 46 cases of hemoglobin SE compound heterozygosity have been reported. No deaths from the condition have been reported previously, whereas death after vigorous physical activity in individuals with sickle cell trait (hemoglobin AS) has been described in a few case reports. Here we report previously undiagnosed hemoglobinopathy SE in a 12-year-old American boy who collapsed during football practice and had a cardiac arrest on the field after a brief lucid interval. The autopsy was significant only for postmortem intravascular sickling. A postmortem hemoglobin electrophoresis test revealed 57% S, 34% E, and 1% F hemoglobins. The death is attributed to cardiac ischemia from functional vaso-occlusion by sickled erythrocytes.

The first case of Hb G-Honolulu [α30(B11)Glu→Gln (GAG>CAG); HBA2:c.91G>A] observed in association with Hb S [β6(A3)Glu→Val, GAG>GTG] in a healthy Italian child

We report the first observation of Hb G-Honolulu [α30(B11)Glu→Gln (GAG>CAG); HBA2:c.91G>A] in a Caucasian family and the first case of this variant to be found in association with Hb S [β6(A3)Glu→Val, GAG>GTG]. The proband was a healthy 4-year-old Italian boy. His chromatographic hemoglobin (Hb) pattern showed an abnormal peak having the typical retention time of Hb S (25.6% ), a second abnormal peak eluted soon after (13.6%) and a third minor peak eluted at the end of the run (6.5%). Identification of Hb variants were performed by peptide mapping using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Two abnormal peptides at m/z 765.1 and 922 were found, corresponding to the αT-4 and βT-1 peptides characteristic for Hb G-Honolulu and Hb S, respectively. The third minor abnormal peak presumably corresponded to the hybrid molecule (α(G-Honolulu)/β(S)). The concomitant presence of Hb G-Honolulu and Hb S does not seem to produce any relevant clinical manifestation.

Sickle cell considerations in athletes

This article highlights the exertional-sickling collapse syndrome in athletes with sickle cell trait (SCT). It covers all aspects of this syndrome, including pathophysiology, new research on microcirculatory changes, clinical features, differential diagnosis, prevention, and treatment. Also covered in this article are other clinical concerns for athletes with SCT, including lumbar myonecrosis, splenic infarction, hematuria, hyposthenuria, and venous thromboembolism. The final section offers practical points on athletes with sickling hemoglobinopathies more serious than SCT.

Sickle-cell disease

Sickle-cell disease is one of the most common severe monogenic disorders in the world. Haemoglobin polymerisation, leading to erythrocyte rigidity and vaso-occlusion, is central to the pathophysiology of this disease, although the importance of chronic anaemia, haemolysis, and vasculopathy has been established. Clinical management is basic and few treatments have a robust evidence base. One of the main problems of sickle-cell disease in children is the development of cerebrovascular disease and cognitive impairment, and the role of blood transfusion and hydroxycarbamide for prevention of these complications is starting to be understood. Recurrent episodes of vaso-occlusion and inflammation result in progressive damage to most organs, including the brain, kidneys, lungs, bones, and cardiovascular system, which becomes apparent with increasing age. Most people with sickle-cell disease live in Africa, where little is known about this disease; however, we do know that the disorder follows a more severe clinical course in Africa than for the rest of the world and that infectious diseases have a role in causing this increased severity of sickle-cell disease. More work is needed to develop effective treatments that specifically target pathophysiological changes and clinical complications of sickle-cell disease.

Hemoglobin e syndromes

Hemoglobin (Hb) E is one of the world's most common and important mutations. It results in a heterogeneous group of disorders whose phenotype range from asymptomatic to severe. Hb E trait and Hb EE are mild disorders. The combination of Hb E and Hb S (Hb SE) results in a sickle cell disease syndrome similar to sickle beta(+) thalassemia. It is important to distinguish Hb E disorders diagnostically because of this marked difference in clinical course among different genotypes. Screening tests, including hemoglobin electrophoresis and high-pressure liquid chromatography (HPLC), may suggest other mutations, unless one is familiar with the findings. E beta-thalassemia, the most serious form of E syndromes, affects a million people worldwide and is increasing in North America. Its phenotype ranges from mild anemia to severe transfusion-dependent thalassemia major. Several genetic modifiers affect the phenotype, including the type of beta-thalassemia mutation, Hb F levels, and co-inheritance of alpha-thalassemia. However, the cause of the phenotypic variability is largely unknown. A prospective natural history study of E beta-thalassemia in Sri Lanka suggests that environmental modifiers are prognostically important. The clinical course of E beta-thalassemia is punctuated by acute and chronic complications that may cause serious morbidity and mortality. Recent studies indicate these patients are at high risk for thromboembolism secondary to a hypercoagulable state increased by splenectomy. Morbidity from iron overload in nontransfused patients secondary to increased gastrointestinal iron absorption is common. Cardiopulmonary disease, including pulmonary hypertension, requires ongoing monitoring and is secondary to iron overload, thromboembolism, and hemolysis-induced nitric oxide deficiency. These patients are excellent candidates for Hb F-modulating agents because moderate changes in hemoglobin may result in marked improvement in phenotype. Recent studies with hydroxyurea indicate 40% of patients will clinically improve with hydroxyurea.