Hemoglobin Variant HbE Found in Two South Asian Diabetic Patients (original) (raw)
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Libyan Journal of Medicine, 2014
Background: In Tunisia, diabetes mellitus and hemoglobinopathies are major public health problems. Glycated hemoglobin (HbA1c) is recommended for long-term monitoring of diabetes mellitus, but the presence of hemoglobin variants may interfere with HbA1c measurement. The aim was to determine the prevalence of hemoglobin variants in Tunisian diabetics and optimize the monitoring of diabetics using HbA1c. Methods: The study enrolled 9,792 Tunisian diabetic patients. HbA1c was measured by cation-exchange highpressure liquid chromatography (HPLC). All the chromatograms were analyzed for the presence of Hb variants. Results: We identified 228 cases (2.33%) of Hb variants with D-10 HPLC (Bio-Rad): 191 with HbA/S trait, 27 with HbA/C trait, and 10 hemoglobin variants with the mention 'Variant-Window' on the chromatograms and subsequently identified as HbA/S on Variant I HPLC (Bio-Rad). Thus, the prevalence of HbS was 2.05%. We did not find any homozygous variant. All HbA1c results were reported to the treating physician. Conclusions: To evaluate glycated hemoglobin in populations with a high prevalence of hemoglobinopathies, we should use the HPLC method, which is easy, economical, and reliable. Based on an algorithm, hemoglobin variants visualized on HPLC should be reported to the physician to improve the management of patients.
Asian Journal of Medical Sciences
Background: Several forms of hemoglobin variants might be present in the population being fully or partially silent. Furthermore, a high percentage of the population is already suffering from type 2 diabetes mellitus (DM) which is mainly monitored by HbA1cestimation. As the structure of hemoglobin molecule is altered by the variant status hence, this might have an impact on the HbA1c estimation. Aims and Objectives: The study aimed to assess the prevalence of hemoglobin variant and its effect on the HbA1c estimation. Materials and Methods: Samples from 439 individuals were taken and evaluated for any hemoglobin variants,andalso, the HbA1c values were measured. Results: About 27.4% of the study population were found to have hemoglobin variants, out of this 27.4%, 19.5% were Hb E carrier and 6.45% were Hb E diseased. About 22.3% of the population were suffering from DM. Hb variants had significant effect on HbA1C measurement in the overall study population and in the normal population...
Diabetes, 2014
Glycated hemoglobin (HbA 1C ) is used as a measure of glycemic control and also as a diagnostic criterion for diabetes mellitus. To discover novel loci harbouring common variants associated with HbA 1C in East Asians, we conducted a meta-analysis of 13 genome wide association studies (N=21,026). We replicated our findings in 3 additional studies comprising 11,576 individuals of East Asian ancestry. 10 variants showed associations that reached genome wide significance in the discovery dataset of which 9 [4 novel variants at TMEM79 (P-value 1.3 × 10 -23 ), HBS1L/MYB (8.5 × 10 -15 ), MYO9B (9.0 × 10 -12 ) and CYBA (1.1 × 10 -8 ) as well as 5 variants at loci that had been previously identified (CDKAL1, G6PC2/ABCB11, GCK, ANK1, and FN3K)] showed consistent evidence of association in Page 7 of 75 For Peer Review Only Diabetes 9 © replication datasets. These variants explained 1.76% of the variance in HbA 1C. Several of these variants (TMEM79, HBS1L/MYB, CYBA, MYO9B, ANK1, and FN3K) showed no association with either blood glucose or type 2 diabetes. Amongst individuals with nondiabetic levels of fasting glucose (<7.0 mmol/l) but elevated (>=6.5%) HbA 1c , 36.1% had HbA1C<6.5% after adjustment for these 6 variants. . Our East Asian GWAS meta-analysis has identified novel variants associated with HbA 1C as well as demonstrating that the effects of known variants are largely transferable across ethnic groups. Variants affecting erythrocyte parameters rather than glucose metabolism may be relevant to the use of HbA 1C for diagnosing diabetes in these populations.
Irish Journal of Medical Science, 2022
HbA1c is the established test for monitoring glycaemic control in diabetes, and intervention trials studying the impact of treatment on glycaemic control and risk of complications focus predominantly on this parameter in terms of evaluating the glycaemic outcomes. It is also the main parameter used when targets for control are being individualised, and more recently, it has been used for the diagnosis of type 2 diabetes. For laboratories performing this test and clinicians utilising it in their decision-making process, a thorough understanding of factors that can impact on the accuracy, and appropriate interpretation of the test is essential. The changing demographic in the Irish population over the last two decades has brought this issue sharply into focus. It is therefore timely to review the utility, performance and interpretation of the HbA1c test to highlight factors impacting on the results, specifically the impact of haemoglobin variants, and the impact of these factors on its utilisation in clinical practice.
Diagnostic Dilemma of HbA1c Detection in Presence of a Hemoglobinopathy: A Case Report
Indian Journal of Clinical Biochemistry, 2010
We report a case of a diabetic, heterozygote with near normal hematology, marginally low level of hemoglobin A 2 (HbA 2) having an increased level of hemoglobin F(HbF) that was pancellularly distributed among the red cells. BioRad DiaSTAT measurements gave a high glycated hemoglobin A1c(HbA1c) of 31.5% and the BioRad Variant analyzer recorded an HbA1c value which was very low, in discordance with the detected blood glucose levels. Flow cytometry and polymerization chain reaction (PCR) based studies were carried out which revealed the case to be that of the common hereditary persistence of fetal hemoglobin (HPFH)-3, an Asian Indian mutation. Fructosamine estimation and HbA1c by Boronate affinity chromatography were able to resolve the discordant value detected and was able to confirm the diabetes status. The case would have been a diagnostic dilemma, if reported without correlation. Keywords Glycated hemoglobin A1c(HbA1c) Á Flow cytometry Á Fluorescein isothiocyanate (FITC) Á Gap polymerization chain reaction (Gap-PCR) Á Alkaline electrophoresis Á Hereditary persistence of fetal hemoglobin (HPFH) Á High performance liquid chromatography (HPLC)
PLoS ONE, 2014
Background: Hemoglobin (Hb) variants are structurally inherited changes of globin chains. Accurate diagnoses of these variants are important for planning of appropriate management and genetic counseling. Since no epidemiological study has been conducted before, we have investigated frequencies, molecular and hematological features of Hb variants found in a large cohort of Thai subjects. Materials and Methods: Study was conducted on 26,013 unrelated subjects, inhabiting in all geographical parts of Thailand over a period of 11 years from January 2002-December 2012. Hb analysis was done on high performance liquid chromatography (HPLC) or capillary electrophoresis (CE). Mutations causing Hb variants were identified using PCR and related techniques. Results: Among 26,013 subjects investigated, 636 (2.4%) were found to carry Hb variants. Of these 636 subjects, 142 (22.4%) carried a-chain variants with 13 different mutations. The remaining included 451 (70.9%) cases with 16 b-chain variants, 37 (5.8%) cases with Hb Lepore (db-hybrid Hb) and 6 (0.9%) cases with a single d-chain variant. The most common a-globin chain variant was the Hb Q-Thailand (a 74GAC-CAC, Asp-His) which was found in 101 cases (15.8%). For b-globin chain variants, Hb Hope (b 136GGT-GAT, Gly-Asp) and Hb Tak (b 146+AC, Ter-Thr) are the two most common ones, found in 121 (19.0%) and 90 (14.2%) cases, respectively. Seven Hb variants have never been found in Thai population. Hb analysis profiles on HPLC or CE of these variants were illustrated to guide presumptive diagnostics. Conclusions: Hb variants are common and heterogeneous in Thai population. With varieties of thalassemias and hemoglobinopathies in the population, interactions between them leading to complex syndromes are common and render their diagnoses difficult in routine practices. Knowledge of the spectrum, molecular basis, genotype-phenotype correlation and diagnostic features should prove useful for prevention and control of the diseases in the region.
IOSR Journal of Dental and Medical Sciences, 2013
Background: Glycated Hemoglobin (HbA 1c) gives an estimate of long-term average glycaemic status. It is used routinely to assess glycaemic control in diabetics to attain treatment goals and prevent long term complications. The purpose of this study is to determine the Chromatographic pattern of Glycated hemoglobin seen in a patient population at the Federal Medical Center Umuahia using the D-10 High Performance Liquid Chromatography machine. Methodology/Results: This is a descriptive study in which seventy consecutive patients attending the medical outpatient clinic of the Federal Medical Center, Umuahia were recruited. The study population comprises of 31 (44.3%) males and 39 (44.3%) females. All the study subjects were adults with majority of them (24.3%) between the age group of 20-30 years. This study revealed that 4.3% of patients had HbA 1c values of less than 4% while 18.6% had high values of 8% and above. Majority of the patients (48.6%) had HbA 1c values between 4-6%. Also 33.8% of the study population was known to have Type 2 DM while 66.2% were not known diabetic patients: 69.6% of diabetics had HbA 1c values greater than 7%. Majority of the patients not known to have diabetes had HbA 1c values less than 7%, however 11.1% of the patients who were not previously known to have diabetes had HbA 1c levels greater than 7%. Conclusion: The HbA 1c assay provides an accurate, precise measure of chronic glycaemic levels and in our environment, using HbA 1c for the diagnosis of diabetes could increase the target population for preventive and therapeutic measures. The National Health Insurance policy should be strengthened and implemented in order to assist the poor and socially disadvantaged in getting adequate healthcare.
Effects of hemoglobin C, D, E, and S traits on measurements of HbA1c by six methods
2012
Dear editor Glycated hemoglobin is hemoglobin that has been irreversibly modified by addition of glucose through a non-enzymatic process and provides a weighted average of plasma glucose concentration over the erythrocyte lifespan. HbA 1c is a specific glycated hemoglobin that is modified at the N-terminal valine of the Hb beta chains. HbA 1c therefore provides a useful estimate of mean glycemia in patients with diabetes that has been shown to be directly related to risks for diabetes complications. Treatment goals for HbA 1c have been established, and more recently the test has been recommended for use in diagnosing diabetes (1,2). Therefore, accurate and precise measurement of HbA 1c is extremely important. The most common hemoglobin variants worldwide are HbS, HbE, HbC and HbD traits. Previous studies have shown method-specific analytic interference with HbA 1c results from these heterozygous hemoglobin variants. This study was approved by the University of Utah Institutional Review Board. Whole blood samples from individuals homozygous for HbA (n=42) and heterozygous for HbC, HbD, HbE, or HbS trait (n=23, n=41, n=76, n=40, respectively) were collected in EDTA tubes. Samples were frozen at −70°C in small aliquots and shipped on dry ice to 4 sites for HbA 1c analysis. Hemoglobin variants were identified by inspection of chromatograms obtained with a Bio-Rad Variant analyzer (Bio-Rad Laboratories, Hercules, CA) using the β Thal Short Program; samples with HbF >5% were excluded. Samples with HbA 1c concentrations of 4-12% were included in this study.