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Effect of HbE trait on measurement of HbA1c by three different methods

Azizi A, Sthaneshwar P, Shanmugam H, Arumugam S

Pathology, 2015 Aug;47(5):495-7.
PMID: 26126045 DOI: 10.1097/PAT.0000000000000286
Matched MeSH terms: Hemoglobin E/genetics*
Effect of HbE heterozygosity on the measurement of HbA1c

Sthaneshwar P, Shanmugam H, Swan VG, Nasurdin N, Tanggaiah K

Pathology, 2013 06;45(4):417-9.
PMID: 23635828 DOI: 10.1097/PAT.0b013e32836142eb

AIM: Measurement of HbA1c provides an excellent measure of glycaemic control for diabetic patients. However, haemoglobin (Hb) variants are known to interfere with HbA1c analysis. In our laboratory HbA1c measurement is performed by Variant II turbo 2.0. The aim of this study is to investigate the influence of HbE trait on HbA1c analysis.
METHODS: Haemoglobin variants were identified by HbA1c analysis in 93 of 3522 samples sent to our laboratory in a period of 1 month. Haemoglobin analysis identified HbE trait in 81 of 93 samples. To determine the influence of HbE trait on HbA1c analysis by Variant II Tubo 2.0, boronate affinity high performance liquid chromatography (HPLC) method (Primus PDQ) was used as the comparison method. Two stage linear regression analysis, Bland Altman plot and Deming regression analysis were performed to analyse whether the presence of HbE trait produced a statistically significant difference in the results. The total allowable error for HbA1c by the Royal Australasian College of Pathologists (RCPA) external quality assurance is 5%. Hence clinically significant difference is more than 5% at the medical decision level of 6% and 9%.
RESULTS: Statistically and clinically significant higher results were observed in Variant II Turbo 2.0 due to the presence of HbE trait. A positive bias of ∼10% was observed at the medical decision levels.
CONCLUSION: Laboratories should be cautious when evaluating HbA1c results in the presence of haemoglobin variants.

Matched MeSH terms: Hemoglobin E/genetics*
RBC-Y/MCV as a discriminant function for differentiating carriers of thalassaemia and HbE from iron deficiency

Nadarajan VS, Sthaneshwar P, Jayaranee S

Int J Lab Hematol, 2010 Apr;32(2):215-21.
PMID: 19566741 DOI: 10.1111/j.1751-553X.2009.01174.x

Individuals with alpha-thalassaemia (ATT), beta-thalassaemia (BTT) and HbE trait (HET) are often initially identified based on haematological parameters. However, the values of these parameters usually overlap with iron deficiency anaemia (IDA) and anaemia of chronic disease (ACD). We evaluated the use of RBC-Y in 156 normal individuals and 332 patients; ATT (n = 37), BTT (n = 61), HET (n = 25), HbH disease (n = 5), ACD (n = 67), IDA (n = 83) and ACD with IDA (n = 54). Diagnostic efficiency was analysed by receiver operating characteristics (ROC). MCH was better compared with RBC-Y in discriminating normal from abnormal with sensitivity and specificity of 94% at a cut-off of 26 pg. The Green and King (G&K) index performed the best in discriminating carriers from IDA and ACD with area under the ROC curve (AUC(ROC)) of 0.81. However, if ACD was excluded, RBC-Y/MCV was a good discriminator for carriers from IDA with AUC(ROC) = 0.845. In general screening of populations with ATT, BTT and HET, we propose that hypochromic individuals be first identified by MCH <26 pg and carriers distinguished within these hypochromic individuals from IDA by using RBC-Y/MCV. However, if the prevalence of ACD were high within the screening population, G&K index would be a more suitable discriminator.

Matched MeSH terms: Hemoglobin E/genetics*
HbA2 levels in normal, beta-thalassaemia and haemoglobin E carriers by capillary electrophoresis

Hafiza A, Malisa MY, Khirotdin RD, Azlin I, Azma Z, Thong MC, et al.

Malays J Pathol, 2012 Dec;34(2):161-4.
PMID: 23424780

The capillary electrophoresis (CE) is a new system that utilizes the principle of electrokinetic separation of molecules in eight electrolyte buffer-filled silica capillaries. In this study, we established the normal ranges of haemoglobin A2 (HbA2) and haemoglobin F (HbF) levels for normal individuals using this system and also the HbA2 level in beta thalassaemia and haemoglobin E (HbE) individuals.

Matched MeSH terms: Hemoglobin E/genetics
Fulltext The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan

Abdullah WA, Jamaluddin NB, Kham SK, Tan JA

Southeast Asian J. Trop. Med. Public Health, 1996 Mar;27(1):164-8.
PMID: 9031421

The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan (Northeast Malaysia) was studied. Allele specific priming was used to determine the mutations in beta-carriers at -28, Codon 17, IVSI #1, IVSI #5, Codon 41-42 and IVSII #654 along the beta-globin gene. The most common structural hemoglobin variant in Southeast Asia, Hb E, was detected by DNA amplification with restriction enzyme (Mnl1) analysis. Direct genomic sequencing was carried out to detect the beta-mutations uncharacterized by allele-specific priming. The most prevalent beta-mutations in Singaporean Malays were IVSI #5 (45.83%) followed by Hb E (20.83%), codon 15 (12.5%) and IVSI #1 and IVSII #654 at 4.17% each. In contrast, the distribution of the beta-mutations in Kelantan Malays differed, with Hb E as the most common mutation (39.29%) followed by IVSI #5 (17.86%), codon 41-42 (14.29%), codon 19 (10.71%) and codon 17 (3.57%). The beta-mutations in Kelantan Malays follow closely the distribution of beta-mutations in Thais and Malays of Southern Thailand and Malays of West Malaysia. The AAC-->AGC base substitution in codon 19 has been detected only in these populations. The spectrum of beta-mutations in the Singaporean Malays is more similar to those reported in Indonesia with the beta-mutation at codon 15 (TGG-->TAG) present in both populations. The characterization of beta-mutations in Singaporean and Kelantan Malays will facilitate the establishment of effective prenatal diagnosis programs for beta-thalassemia major in this ethnic group.

Matched MeSH terms: Hemoglobin E/genetics
Malays with thalassaemia in West Malaysia

George E, Khuziah R

Trop Geogr Med, 1984 Jun;36(2):123-5.
PMID: 6332395

Hereditary haemolytic anaemias have been found to be a significant cause of haemolytic disease in West Malaysia. This paper reports a micromapping study of 916 healthy Malay males from June to August 1983 to determine the distribution of the relevant thalassaemia genes in West Malaysia. Beta thalassaemia trait was found in 2.18%, HbE 3.49% and alpha thal2 (alpha+) trait in 26%. Of the sixteen transfusion dependant Malay thalassaemic patients at the Paediatric Unit, National University of Malaysia, eight patients had HbE beta thalassaemia and the rest are beta thalassaemia major; these patients who are transfusion dependant receive inadequate treatment. Prevention is the only resort.

Matched MeSH terms: Hemoglobin E/genetics
Kin groups and trait groups: population structure and epidemic disease selection

Fix AG

Am. J. Phys. Anthropol., 1984 Oct;65(2):201-12.
PMID: 6507610

A Monte Carlo simulation based on the population structure of a small-scale human population, the Semai Senoi of Malaysia, has been developed to study the combined effects of group, kin, and individual selection. The population structure resembles D.S. Wilson's structured deme model in that local breeding populations (Semai settlements) are subdivided into trait groups (hamlets) that may be kin-structured and are not themselves demes. Additionally, settlement breeding populations are connected by two-dimensional stepping-stone migration approaching 30% per generation. Group and kin-structured group selection occur among hamlets the survivors of which then disperse to breed within the settlement population. Genetic drift is modeled by the process of hamlet formation; individual selection as a deterministic process, and stepping-stone migration as either random or kin-structured migrant groups. The mechanism for group selection is epidemics of infectious disease that can wipe out small hamlets particularly if most adults become sick and social life collapses. Genetic resistance to a disease is an individual attribute; however, hamlet groups with several resistant adults are less likely to disintegrate and experience high social mortality. A specific human gene, hemoglobin E, which confers resistance to malaria, is studied as an example of the process. The results of the simulations show that high genetic variance among hamlet groups may be generated by moderate degrees of kin-structuring. This strong microdifferentiation provides the potential for group selection. The effect of group selection in this case is rapid increase in gene frequencies among the total set of populations. In fact, group selection in concert with individual selection produced a faster rate of gene frequency increase among a set of 25 populations than the rate within a single unstructured population subject to deterministic individual selection. Such rapid evolution with plausible rates of extinction, individual selection, and migration and a population structure realistic in its general form, has implications for specific human polymorphisms such as hemoglobin variants and for the more general problem of the tempo of evolution as well.

Matched MeSH terms: Hemoglobin E/genetics
Fulltext Homozygous haemoglobin E in association with hereditary ovalocytosis

George E, Kudva MV

Med J Malaysia, 1989 Sep;44(3):255-8.
PMID: 2626141

Hereditary stomatocytic ovalocytosis and haemoglobin E are two genes present in 3-5% of Malays. This is a report of a 22 year old Malay college student with homozygous haemoglobin E and hereditary stomatocytic ovalocytosis where the clinical effects seen were the result of the summation of these genes: he was asymptomatic, presenting with moderate jaundice, moderate hepatosplenomegaly, and a mild haemolytic anaemia.

Matched MeSH terms: Hemoglobin E/genetics*
Kin-structured migration: causes and consequences

Fix AG

Am J Hum Biol, 2004 Jul-Aug;16(4):387-94.
PMID: 15214057

Migration among local populations classically has been seen as the principal process retarding genetic microdifferentiation. However, as Sewall Wright pointed out long ago, migration may also act as a random differentiating force. In fact, when migrants comprise a biological kin group, migration may be considered a component of genetic drift. The causes of kin-structured migration (KSM) lie in the common, if not universal, tendency for kin to associate and cooperate. However, similar to genetic drift, KSM has its greatest effect in smaller populations and is most apparent in low-density fission-fusion societies such as the Yanomamo of South America and the Semai of Malaysia, and less salient in higher density, low-mobility populations such as those of the New Guinea Highlands. The evolutionary consequences of KSM begin with increased genetic variation among populations. Such intergroup variation provides a basis for group selection. The origin of larger-scale geographic differentiation can arise from kin-structured migrant groups colonizing new regions. Waves of colonizing kin-structured founder groups may produce gene frequency clines, mimicking demic diffusion and natural selection. Finally, because kin structuring reduces the effective size of a population, it may be speculated that the extremely small effective size inferred for ancestral populations of Homo sapiens may be an artifact of kin-structured demographically larger populations.

Matched MeSH terms: Hemoglobin E/genetics
Fulltext HbE/β-Thalassemia and Oxidative Stress: The Key to Pathophysiological Mechanisms and Novel Therapeutics

Hirsch RE, Sibmooh N, Fucharoen S, Friedman JM

Antioxid Redox Signal, 2017 05 10;26(14):794-813.
PMID: 27650096 DOI: 10.1089/ars.2016.6806

SIGNIFICANCE: Oxidative stress and generation of free radicals are fundamental in initiating pathophysiological mechanisms leading to an inflammatory cascade resulting in high rates of morbidity and death from many inherited point mutation-derived hemoglobinopathies. Hemoglobin (Hb)E is the most common point mutation worldwide. The βE-globin gene is found in greatest frequency in Southeast Asia, including Thailand, Malaysia, Indonesia, Vietnam, Cambodia, and Laos. With the wave of worldwide migration, it is entering the gene pool of diverse populations with greater consequences than expected.
CRITICAL ISSUES: While HbE by itself presents as a mild anemia and a single gene for β-thalassemia is not serious, it remains unexplained why HbE/β-thalassemia (HbE/β-thal) is a grave disease with high morbidity and mortality. Patients often exhibit defective physical development, severe chronic anemia, and often die of cardiovascular disease and severe infections. Recent Advances: This article presents an overview of HbE/β-thal disease with an emphasis on new findings pointing to pathophysiological mechanisms derived from and initiated by the dysfunctional property of HbE as a reduced nitrite reductase concomitant with excess α-chains exacerbating unstable HbE, leading to a combination of nitric oxide imbalance, oxidative stress, and proinflammatory events.
FUTURE DIRECTIONS: Additionally, we present new therapeutic strategies that are based on the emerging molecular-level understanding of the pathophysiology of this and other hemoglobinopathies. These strategies are designed to short-circuit the inflammatory cascade leading to devastating chronic morbidity and fatal consequences. Antioxid. Redox Signal. 26, 794-813.

Matched MeSH terms: Hemoglobin E/genetics
Molecular characterization of beta-globin gene mutations in Malay patients with Hb E-beta-thalassaemia and thalassaemia major

Yang KG, Kutlar F, George E, Wilson JB, Kutlar A, Stoming TA, et al.

Br J Haematol, 1989 May;72(1):73-80.
PMID: 2736244

This study concerned the identification of the beta-thalassaemia mutations that were present in 27 Malay patients with Hb E-beta-thalassaemia and seven Malay patients with thalassaemia major who were from West Malaysia. Nearly 50% of all beta-thalassaemia chromosomes carried the G----C substitution at nucleotide 5 of IVS-I; the commonly occurring Chinese anomalies such as the frameshift at codons 41 and 42, the nonsense mutation A----T at codon 17, the A----G substitution at position -28 of the promoter region, and the C----T substitution at position 654 of the second intron, were rare or absent. Two new thalassaemia mutations were discovered. The first involves a frameshift at codon 35 (-C) that was found in two patients with Hb E-beta zero-thalassaemia and causes a beta zero-thalassaemia because a stop codon is present at codon 60. The second is an AAC----AGC mutation in codon 19 that was present on six chromosomes. This substitution results in the production of an abnormal beta chain (beta-Malay) that has an Asn----Ser substitution at position beta 19. Hb Malay is a 'Hb Knossos-like' beta +-thalassaemia abnormality; the A----G mutation at codon 19 likely creates an alternate splicing site between codons 17 and 18, reducing the efficiency of the normal donor splice site at IVS-I to about 60%.

Matched MeSH terms: Hemoglobin E/genetics*
Fulltext Chinese in west Malaysia: the geography of beta thalassaemia mutations

George-Kodiseri E, Yang KG, Kutlar F, Wilson JB, Kutlar A, Stoming TA, et al.

Singapore Med J, 1990 Aug;31(4):374-7.
PMID: 2255937

The overseas Chinese in West Malaysia are almost exclusively from the south-eastern provinces of China-Kwangtung, Fukien, and Kwangsi. To institute a comprehensive thalassaemia control programme for this region we have characterised the beta thalassaemia mutations in 16 Chinese patients from West Malaysia: 4 beta thalassaemia mutations were seen: a) an A----G substitution in the TATA box [-28 base pairs (bp)], an A----T substitution in codon 17 [17 A----T], c) a 4 base pairs - TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)], and d) a C----T substitution at the second intervening sequence (IVS 11) position 654. Similar mutations have been described in patients from the south-eastern provinces of China. The delineation of the specific mutations present will enable effective prenatal diagnosis for beta thalassaemia of ethnic Chinese in West Malaysia to be instituted.

Matched MeSH terms: Hemoglobin E/genetics
α-Haemoglobin stabilising protein expression is influenced by mean cell haemoglobin and HbF levels in HbE/β-thalassaemia individuals

Lim WF, Muniandi L, George E, Sathar J, Teh LK, Gan GG, et al.

Blood Cells Mol. Dis., 2012 Jan 15;48(1):17-21.
PMID: 22079025 DOI: 10.1016/j.bcmd.2011.10.002

The alpha haemoglobin stabilising protein (AHSP) acts as a molecular chaperone for α-globin by stabilising nascent α-globin before transferring it to waiting free β-globin chains. Binding of AHSP to α-globin renders α-globin chemically inert whereby preventing it from precipitating and forming reactive oxygen species byproducts. The AHSP has been actively studied in the recent years, particularly in its relation to β-thalassaemia. Studies have shown that AHSP is a modifier in β-thalassaemia mice models. However, this relationship is less established in humans. Studies by some groups showed no correlation between the AHSP haplotypes and the severity of β-thalassaemia, whereas others have shown that certain AHSP haplotype could modify the phenotype of β-thalassaemia intermedia patients. We investigated the expression of AHSP in relation to selected demographic data, full blood count, HPLC results, HbE/β-thalassaemia genotype, Xmn-1 Gγ polymorphism, α-globin, β-globin and γ-globin expression. We found that AHSP expression was significantly correlated to mean cell haemoglobin level, HbF %, α-globin, β-globin and excess α-globin expression. We concluded that AHSP could be a secondary compensatory mechanism in red blood cells to counterbalance the excess α-globin chains in HbE/β-thalassaemia individuals.

Matched MeSH terms: Hemoglobin E/genetics*
Genotype-Phenotype Correlation of β-Thalassemia in Malaysian Population: Toward Effective Genetic Counseling

Abdullah UYH, Ibrahim HM, Mahmud NB, Salleh MZ, Teh LK, Noorizhab MNFB, et al.

Hemoglobin, 2020 May;44(3):184-189.
PMID: 32586164 DOI: 10.1080/03630269.2020.1781652

Effective prevention of β-thalassemia (β-thal) requires strategies to detect at-risk couples. This is the first study attempting to assess the prevalence of silent β-thal carriers in the Malaysian population. Hematological and clinical parameters were evaluated in healthy blood donors and patients with β-thal trait, Hb E (HBB: c.79G>A)/β-thal and β-thal major (β-TM). β-Globin gene sequencing was carried out for 52 healthy blood donors, 48 patients with Hb E/β-thal, 34 patients with β-TM and 38 patients with β-thal trait. The prevalence of silent β-thal carrier phenotypes found in 25.0% of healthy Malaysian blood donors indicates the need for clinician's awareness of this type in evaluating β-thal in Malaysia. Patients with β-TM present at a significantly younger age at initial diagnosis and require more blood transfusions compared to those with Hb E/β-thal. The time at which genomic DNA was extracted after blood collection, particularly from patients with β-TM and Hb E/β-thal, was found to be an important determinant of the quality of the results of the β-globin sequencing. Public education and communication campaigns are recommended as apparently healthy individuals have few or no symptoms and normal or borderline hematological parameters. β-Globin gene mutation characterization and screening for silent β-thal carriers in regions prevalent with β-thal are recommended to develop more effective genetic counseling and management of β-thal.

Matched MeSH terms: Hemoglobin E/genetics
Fulltext Correlation of BACH1 and Hemoglobin E/Beta-Thalassemia Globin Expression

Lee TY, Muniandy L, Teh LK, Abdullah M, George E, Sathar J, et al.

Turk J Haematol, 2016 Mar 05;33(1):15-20.
PMID: 26377036 DOI: 10.4274/tjh.2014.0197

The diverse clinical phenotype of hemoglobin E (HbE)/β-thalassemia has not only confounded clinicians in matters of patient management but has also led scientists to investigate the complex mechanisms involved in maintaining the delicate red cell environment where, even with apparent similarities of α- and β-globin genotypes, the phenotype tells a different story. The BTB and CNC homology 1 (BACH1) protein is known to regulate α- and β-globin gene transcriptions during the terminal differentiation of erythroid cells. With the mutations involved in HbE/β-thalassemia disorder, we studied the role of BACH1 in compensating for the globin chain imbalance, albeit for fine-tuning purposes.

Matched MeSH terms: Hemoglobin E/genetics*
Molecular basis of beta-thalassemia in the Maldives

Furuumi H, Firdous N, Inoue T, Ohta H, Winichagoon P, Fucharoen S, et al.

Hemoglobin, 1998 Mar;22(2):141-51.
PMID: 9576331

We have systematically analyzed beta-thalassemia genes using polymerase chain reaction-related techniques, dot-blot hybridization with oligonucleotide probes, allele specific-polymerase chain reaction, and sequencing of amplified DNA fragments from 41 unrelated patients, including 37 beta-thalassemia homozygotes, three with beta-thalassemia/Hb E, and one with beta-thalassemia/Hb S. Four different beta-thalassemia mutations were detected in 78 alleles. These are the IVS-I-5 (G-->C), codon 30 (AGG-->ACG) [also indicated as IVS-I (-1)], IVS-I-1 (G-->A), and codons 41/42 (-TTCT) mutations. The distribution of the beta-thalassemia mutations in the Maldives is 58 alleles (74.3%) with the IVS-I-5 (G-->C) mutation, 12 (15.4%) with the codon 30 (AGG-->ACG) mutation, seven (9%) with the IVS-I-1 (G-->A) mutation, and one with the codons 41/42 (-TTCT) mutation. The first three mutations account for 98.7% of the total number of beta-thalassemia chromosomes studied. These mutations are clustered in the region spanning 6 bp around the junction of exon 1 and the first intervening sequence of the beta-globin gene. These observations have significant implications for setting up a thalassemia prevention and control program in the Maldives. Analysis of haplotypes and frameworks of chromosomes bearing each beta-thalassemia mutation suggested that the origin and spread of these mutations were reflected by the historical record.

Matched MeSH terms: Hemoglobin E/genetics
Fulltext Predictive SNPs for β0-thalassemia/HbE disease severity

Munkongdee T, Tongsima S, Ngamphiw C, Wangkumhang P, Peerapittayamongkol C, Hashim HB, et al.

Sci Rep, 2021 05 14;11(1):10352.
PMID: 33990643 DOI: 10.1038/s41598-021-89641-2

β-Thalassemia/HbE disease has a wide spectrum of clinical phenotypes ranging from asymptomatic to dependent on regular blood transfusions. Ability to predict disease severity is helpful for clinical management and treatment decision making. A thalassemia severity score has been developed from Mediterranean β-thalassemia patients. However, different ethnic groups may have different allele frequency and linkage disequilibrium structures. Here, Thai β0-thalassemia/HbE disease genome-wild association studies (GWAS) data of 487 patients were analyzed by SNP interaction prioritization algorithm, interacting Loci (iLoci), to find predictive SNPs for disease severity. Three SNPs from two SNP interaction pairs associated with disease severity were identifies. The three-SNP disease severity risk score composed of rs766432 in BCL11A, rs9399137 in HBS1L-MYB and rs72872548 in HBE1 showed more than 85% specificity and 75% accuracy. The three-SNP predictive score was then validated in two independent cohorts of Thai and Malaysian β0-thalassemia/HbE patients with comparable specificity and accuracy. The SNP risk score could be used for prediction of clinical severity for Southeast Asia β0-thalassemia/HbE population.

Matched MeSH terms: Hemoglobin E/genetics*

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