Hb Variants Research Articles

Current and Future Therapeutics for Treating Patients with Sickle Cell Disease.

Sickle cell disease (SCD) is the most common genetic blood disorder in the United States, with over 100,000 people suffering from this debilitating disease. SCD is caused by abnormal hemoglobin (Hb) variants that interfere with normal red blood cell (RBC) function. Research on SCD has led to the development and approval of several new SCD therapies in recent years. The recent FDA-approved novel gene therapies are potentially curative, giving patients an additional option besides a hematopoietic bone marrow transplant. Despite the promise of existing therapies, questions remain regarding their long-term pharmacological effects on adults and children. These questions, along with the exorbitant cost of the new gene therapies, justify additional research into more effective therapeutic options. Continual research in this field focuses on not only developing cheaper, more effective cures/treatments but also investigating the physiological effects of the current therapies on SCD patients, particularly on the brain and kidneys. In this article, we undertake a comprehensive review of ongoing clinical trials with completion dates in 2024 or later. Our exploration provides insights into the landscape of current therapeutics and emerging novel therapies designed to combat and potentially eradicate SCD, including the latest FDA-approved gene therapies.

Molecular epidemiology and hematological profiles of hemoglobin variants in southern Thailand

AbstractData on hemoglobin (Hb) variants in southern Thailand are lacking. This study aimed to reassess the frequency of Hb variants and the clinical aspects of compound heterozygous Hb variant with other hemoglobinopathies. We enrolled 13,391 participants from ten provinces in southern Thailand during 2015–2022. Hb analysis was performed using capillary electrophoresis, and mutations in the HBA and HBB genes were identified using PCR or DNA sequencing. Hb variants were identified in 337 (2.5%) unrelated subjects. Nine β-chain variants, namely Hb Malay (76.9%), Hb C (10.1%), Hb D-Punjab (2.9%), Hb G-Makassar (2.3%), Hb Dhonburi (2.3%), Hb Tak (1.4%), Hb J-Bangkok (1.4%), Hb New York (0.3%), and Hb Hope (0.3%), and four α-chain variants—Hb G-Georgia (HBA1) (0.9%), Hb G-Georgia (HBA2) (0.3%), Hb Q-Thailand (0.6%), and Hb St. Luke’s-Thailand (0.3%)—were identified. The southern population exhibited a distinct spectrum of Hb variants compared to that observed in the populations from other areas. Several compound heterozygous genotypes were also identified. Combining Hb Malay with Hb E or high Hb F determinants did not require a blood transfusion. This study provides essential information for genetic counseling in thalassemia prevention and control programs in this region.

A clinical update of compound heterozygosity for hemoglobin Hekinan II [a27(B8)Glu-Asp; HBA1: c.84G>T] variant in China.

Hemoglobin (Hb) Hekinan II (A27; Glu-Asp) is an α-chain variant, and its interaction with the common Southeast Asian (--SEA/) α-thalassemia (α-thal) deletion is rarely reported. This study provides a clinical update of Hb Hekinan II associated with (--SEA/) α-thal. A total of 11 simple heterozygotes and 20 composite heterozygotes for Hb Hekinan II and (--SEA/) α-thal were included based on molecular diagnosis. Hb Hekinan II exhibited a significant increase in hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin content, but a decrease in red blood cell level compared with α+ thalassemia deletion. Compared with (--SEA/) α-thal, composite heterozygotes for Hb Hekinan II and (--SEA/) α-thal showed similar erythrocyte parameters. Both heterozygotes with and without (--SEA/) α-thal showed low Hb A2 level. Hb Hekinan II showed abnormal performance in high-performance liquid chromatography but not in capillary electrophoresis. Hb Hekinan II is a benign Hb variant. The heterozygotes exhibit clinically asymptomatic coinheritance with (--SEA/) α-thal having comparable hematological phenotype to simple (--SEA/) α-thal. The combination of hematological and molecular analysis helped to improve the detection rate of this rare variant.

Evaluation of effects from hemoglobin variants on HbA1c measurements by different methods.

The impact of seven hemoglobin variants (Hb Q-Thailand, Hb G-Honolulu, Hb Ube-2, Hb New York, Hb J-Bangkok, Hb G-Coushatta, and Hb E) on the outcome of HbA1c was investigated for six methods by comparing withliquid chromatography-tandem mass spectrometry (LC/MS/MS) reference method. Twenty-nine normal and 112 variant samples were measured by LC/MS/MS, Sebia Capillarys 3 TERA, Intelligene Biosystems QuanTOF, Premier Hb9210, Arkray HA-8190V, Bio-Rad D-100, and Tosoh G11, then evaluated for correlation, consistency, and mean relative bias among six methods. The lowest biological variation bias of ±2.8 % was an acceptable standard. All methods showed poor correlation and consistency with LC/MS/MS for Hb E. The unacceptable biases were observed for Capillarys 3 TERA (-14.4 to-3.7 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), QuanTOF (-8.3 to-2.9 % for Hb Ube-2, Hb New York and Hb G-Coushatta), Premier Hb9210 (-18.3 to-3.6 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), HA-8190V variant mode (-17.3 to 6.6 % for Hb G-Honolulu, Hb Ube-2, Hb New York, Hb G-Coushatta and Hb E). All variant samples showed larger biases than ±2.8 % comparing HA-8190V fast mode, D-100, and G11 with LC/MS/MS. The accuracy of different HbA1c methods was influenced by some Hb variants, especially Hb Ube-2 and Hb New York. Thus, laboratories need to choose appropriate methods to measure HbA1c with different Hb variants.

Hemoglobin Variants in Patients Attending Aden Diagnostic Center by High Performance Liquid Chromatography

Introduction: High performance liquid chromatography (HPLC) is emerging as the method of choice for initial screening and diagnosis of hemoglobinopathies. The use of alkaline and acid gel electrophoresis may result in incorrect diagnosis of hemoglobinopathies. The aim of the study is to investigate the hemoglobin pattern using the HPLC and to correlate the hematological profile with the types of hemoglobin. Methods: A cross-sectional study was conducted in Aden Diagnostic Center from July– December 2022. Over a six-month period, 250 samples of patients aged between six months to thirty years, were evaluated by HPLC for detection of hemoglobinopathies using the Lifotronic Hemoglobin Analyzer H9: β-thalassemia Analysis Mode. Red blood cell and red cell indices were determined using automated hematology analyzer. Results: A total of 152 samples (60.8%) showed different abnormal hemoglobin variants. Sixty-four (25.6%) were diagnosed to have sickle cell anemia, 46 (18.4%) as sickle cell trait, two (0.8) as beta – heterozygous thalassemia based on high level of HbA2 (>3.9%), four (1.6%) as beta – homozygous thalassemia (HbF 25–91%), 18 (7.2%) as compound heterozygous state of sickle - β+ thalassemia, 17 (6.8%) as beta thalassemia trait, and one (0.4%) sample had HbD variant on HPLC was diagnosed as HbD trait. Conclusion: H9-HPLC is suitable for the routine investigation of hemoglobinopatheis because it is very powerful tool in the evaluation of Hb variants, rapid assay time and accurate quantification.

Wide spectrum of novel and rare hemoglobin variants in the multi-ethnic Indian population: A review.

The hemoglobin (Hb) variants are qualitative abnormalities due to production of structurally abnormal globin proteins. They are categorized based on the type of mutation present in the α1, α2, β, Gγ, Aγ and δ globin genes. So far, more than 1550 Hb variants are reported in the database. They could lead to Hb polymerization, Hb instability, altered oxygen affinity and decreased oxygen-carrying capacity of Hb or have no clinical manifestations. In India, ethnic diversity, consanguinity, regional variations and migration result in the presence of different Hb variants. We have compiled all the variants of α, β and δ globin chains in heterozygous, homozygous and in compound heterozygous forms reported from India in the last 52 years. Of the 63 rare and novel hemoglobin variants reported from India, 22 were α-globin chain variants, 37 were β-globin chain variants and 4 were δ-globin chain variants. Twelve novel Hb variants (Hb J Rajappan, Hb Koya Dora, Hb Rampa, Hb Godavari, Hb Chandigarh, Hb D Agri, Hb Lucknow, Hb Vellore, Hb Midnapore, Hb Bijnor, Hb A2Tianhe and Hb A2Saurashtra) were identified among persons of Indian origin. Majority of them were picked up on HPLC. Some of the variants like Hb Titusville, Hb Shimonoseki, Hb Chandigarh, Hb D Agri, Hb Yaizu and Hb Vellore eluted in the HbS window whereas variants like HbD Iran, Hb St. Louis, Hb G Coushata, HbM Saskatoon, Hb Lucknow, Hb Grange-Blanche and Hb Tianshui showed falsely elevated HbA2. Hence, careful and systematic investigations are required to identify them.

Immune responses to P falciparum antibodies in symptomatic malaria patients with variant hemoglobin genotypes in Ghana

BackgroundHaemoglobin (Hb) variants such as sickle cell trait (SCT/HbAS) play a role in protecting against clinical malaria, but little is known about the development of immune responses against malaria parasite (Plasmodium falciparum surface protein 230 (Pfs230) and Plasmodium falciparum erythrocyte binding antigen 175 region-3 (PfEBA175-3R)) and vector (on the An. gambiae Salivary Gland Protein-6 peptide 1 (gSG6-P1)) antigens in individuals with variants Hb genotypes. This study assessed antibody (IgG) responses against malaria parasite, Pfs230 and PfEBA175-3R and vector, gSG6-P1 in febrile individuals with variant Hb genotypes.MethodsThe study was conducted on symptomatic malaria patients attending various healthcare facilities throughout Ghana. Microscopy and ELISA were used to determine the natural IgG antibody levels of gSG6-P1, PfEBA175-3R & Pfs230, and Capillarys 2 Flex Piercing was used for Hb variants determination.ResultsOf the 600 symptomatic malaria patients, 50.0% of the participants had malaria parasites by microscopy. The majority 79.0% (398/504) of the participants had Hb AA, followed by HbAS variant at 11.3% (57/504) and HbAC 6.7% (34/504). There were significantly (p < 0.0001) reduced levels of gSG6-P1 IgG in individuals with both HbAC and HbAS genotypes compared to the HbAA genotype. The levels of gSG6-P1 IgG were significantly (p < 0.0001) higher in HbAS compared to HbAC. Similarly, Pfs230 IgG and PfEBA-175-3R IgG distributions observed across the haemoglobin variants were significantly higher in HbAC relative to HbAS.ConclusionThe study has shown that haemoglobin variants significantly influence the pattern of anti-gSG6-P1, Pfs230, and PfEBA-175 IgG levels in malaria-endemic population. The HbAS genotype is suggested to confer protection against malaria infection. Reduced exposure to infection ultimately reduces the induction of antibodies targeted against P. falciparum antigens.

Haemoglobin Ottawa, sickle cell trait and vaso-occlusive crises.

A girl with a sickle cell trait had severe VOCs (vaso-occlusive crises), her father also had a sickle cell trait but mild VOCs, and her mother had no symptoms. Electrophoresis on agarose gel under alkaline conditions showed haemoglobin AS (HbAS) in the girl and in her father, with an S band increased more than expected (46.2% and 41.2% respectively), and a band migrating at C (16.8% and 8.9% respectively) in both. There was a band at S (19.6 %) in her mother. The C band was attributed to a hybrid tetramer with haemoglobin S (HbS) and a Hb variant. A homozygous c.46G>C mutation (Hb Ottawa, the Hb variant) was detected by Sanger sequencing in the girl. Heterozygosity for Hb Ottawa by Sanger sequencing was shown in both the father and the mother. The father, with HbAS and heterozygous for Hb Ottawa, had mild VOCs. Heterozygosity only for Hb Ottawa did not produce any abnormality in the mother. A sister and two brothers of the index patient presented a Hb variant, probably Hb Ottawa, migrating to the S zone (all 20%) at electrophoresis, without HbS. These last three were asymptomatic. We conclude that Hb Ottawa, an α-globin variant, contributes along with haemoglobin S (HbS) to VOC symptoms.

High-Oxygen-Affinity Hemoglobins-Case Series and Review of the Literature.

Modifications of the hemoglobin (Hb) structure in regions involving the regulation of oxygen transport may lead to an increased oxygen affinity for the hemoglobin molecule and impaired oxygen delivery to the tissues. Herein, we present six patients with high-oxygen-affinity Hb variants, either in heterozygous form or in compound heterozygosity (such as heterozygosity for Hb Hiroshima, Köln, Crete, and compound heterozygosity Hb Crete with β or δβ thalassemia), in order to demonstrate the need for prompt and accurate diagnosis and enrich the limited literature due to the rarity of such cases. Hb Crete, Hb Hiroshima, and Hb Köln have distinct pathophysiologies and may result in different clinical phenotypes. In conclusion, high-oxygen-affinity hemoglobins are rare and inherited within a dominant autosomal manner, have various clinical presentations, and should always be suspected in patients with erythrocytosis. Their management (as phlebotomy or low-dose aspirin) should be based on an individualized assessment of the risk of complications, the medical history, concomitant symptoms, and quality of life.

A comparative evaluation of the analytical performances of premier resolution-high-performance liquid chromatography (PR-HPLC) with capillary zone electrophoresis (CZE) assays for the detection of hemoglobin variants and the quantitation of HbA0, A2, E, and F.

Hemoglobinopathies, including thalassemia and hemoglobin (Hb) variants, are common hematological disorders in tropical countries. Accurate and precise separation of hemoglobin types and reliable quantitation are necessary for differential diagnosis of these disorders. We have evaluated the analytical performances of premier resolution-high-performance liquid chromatography (PR-HPLC; Trinity Biotech, Co. Wicklow, Ireland) to assist in the presumptive diagnosis of thalassemia and Hb variants commonly found in Southeast Asian countries. HbA0, HbA2, HbE, and HbF levels were separated and quantified in 120 blood samples from unrelated adult subjects and compared with those analyzed by capillary zone electrophoresis (CZE; CAPILLARYS™ 2, Sebia, Norcross, GA, US). The Hb analysis patterns of Hb variants obtained from the PR-HPLC system were also compared to those obtained from HPLC (VARIANT II, β-thalassemia Short Program, Bio-Rad, Laboratories, Hercules, CA, US) and CZE systems. The PR-HPLC had excellent precision with a coefficient of variation (CV) for HbA2 quantitation of 3.8 % within-run and 5.2 % between-run. The levels of HbA2/E quantified by the PR-HPLC system correlated well with those of the CZE system (r=0.997). In addition, thalassemia interpretation results obtained from the PR-HPLC and the CZE showed 100 % agreement. Moreover, chromatograms of the PR-HPLC were also comparable to those of VII-HPLC and CAP2-CZE electropherograms. The PR-HPLC system would be applicable to diagnose common forms of thalassemia and Hb variants in Southeast Asia.

Two patients with α-chain hemoglobin variant Hb Q-Iran detected by measuring hemoglobin A1c using the variant mode of the HA-8180V HPLC analyzer.

Hemoglobin variants are often discovered when hemoglobin A1c (HbA1c) levels measured with a high-performance liquid chromatography (HPLC) system in fast mode are found to be low. The HA-8180V HPLC analyzer by Arkray offers two measurement modes: fast mode (FM) and variant mode (VM). Two Japanese patients with α-chain variant Hb Q-Iran detected incidentally after analyses with the HA-8180V in VM showed an abnormal peak, are presented. The first patient was a man in his 70s, and the second patient was a man in his 50s. Both were non-diabetic, but their results from HbA1c measurement in VM showed an abnormal peak. The VM-HbA1c, FM-HbA1c, and HbA1c measured by enzymatic assay and glycated albumin levels of the two patients were all within the reference ranges. They were diagnosed as having Hb Q-Iran (α2-75Asp → His) by globin gene analysis. It is difficult to detect α-chain hemoglobin variants based on abnormal FM-HbA1c levels, but measuring HbA1c in VM is useful for efficiently detecting hemoglobin variants.

Rapid measurement of hemoglobin-oxygen dissociation by leveraging Bohr effect and Soret band bathochromic shift.

Oxygen (O2) binds to hemoglobin (Hb) in the lungs and is then released (dissociated) in the tissues. The Bohr effect is a physiological mechanism that governs the affinity of Hb for O2 based on pH, where a lower pH results in a lower Hb-O2 affinity and higher Hb-O2 dissociation. Hb-O2 affinity and dissociation are crucial for maintaining aerobic metabolism in cells and tissues. Despite its vital role in human physiology, Hb-O2 dissociation measurement is underutilized in basic research and in clinical laboratories, primarily due to the technical complexity and limited throughput of existing methods. We present a rapid Hb-O2 dissociation measurement approach by leveraging the Bohr effect and detecting the optical shift in the Soret band that corresponds to the light absorption by the heme group in Hb. This new method reduces Hb-O2 dissociation measurement time from hours to minutes. We show that Hb deoxygenation can be accelerated chemically at the optimal pH of 6.9. We show that time and pH-controlled deoxygenation of Hb results in rapid and distinct conformational changes in its tertiary structure. These molecular conformational changes are manifested as significant, detectable shifts in Hb's optical absorption spectrum, particularly in the characteristic Soret band (414 nm). We extensively validated the method by testing human blood samples containing normal Hb and Hb variants. We show that rapid Hb-O2 dissociation can be used to screen for and detect Hb-O2 affinity disorders and to evaluate the function and efficacy of Hb-modifying therapies. The ubiquity of optical absorption spectrophotometers positions this approach as an accessible, rapid, and accurate Hb-O2 dissociation measurement method for basic research and clinical use. We anticipate this method's broad adoption will democratize the diagnosis and prognosis of Hb disorders, such as sickle cell disease. Further, this method has the potential to transform the research and development of new targeted and genome-editing-based therapies that aim to modify or improve Hb-O2 affinity.

Third-generation sequencing identified two rare α-chain variants leading to hemoglobin variants in Chinese population.

Rare and novel variants of HBA1/2 and HBB genes resulting in thalassemia and hemoglobin (Hb) variants have been increasingly identified. Our goal was to identify two rare Hb variants in Chinese population using third-generation sequencing (TGS) technology. Enrolled in this study were two Chinese families from Fujian Province. Hematological screening was conducted using routine blood analysis and Hb capillary electrophoresis analysis. Routine thalassemia gene testing was carried out to detect the common mutations of α- and β-thalassemia in Chinese population. Rare or novel α- and β-globin gene variants were further investigated by TGS. The proband of family 1 was a female aged 32, with decreased levels of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), Hb A2, and abnormal Hb bands in zone 5 and zone 12. No common thalassemia mutations were detected by routine thalassemia analysis, while a rare α-globin gene variant Hb Jilin [α139(HC1)Lys>Gln (AAA>CAA); HBA2:c.418A>C] was identified by TGS. Subsequent pedigree analysis showed that the proband's son also harbored the Hb Jilin variant with slightly low levels of MCH, Hb A2, and abnormal Hb bands. The proband of family 2 was a male at 41 years of age, exhibiting normal MCV and MCH, but a low level of Hb A2 and an abnormal Hb band in zone 12 without any common α- and β-thalassemia mutations. The subsequent TGS detection demonstrated a rare Hb Beijing [α16(A14)Lys>Asn (AAG>AAT); HBA2:c.51G>T] variant in HBA2 gene. In this study, for the first time, we present two rare Hb variants of Hb Jilin and Hb Beijing in Fujian Province, Southeast China, using TGS technology.

Deep learning ResNet34 model-assisted diagnosis of sickle cell disease via microcolumn isoelectric focusing.

Traditional methods for sickle cell disease (SCD) screening can be inaccurate and misleading, and the early and accurate diagnosis of SCD is crucial for effective management and treatment. Although microcolumn isoelectric focusing (mIEF) is effective, the hemoglobinopathies must be accurately identified, wherein skilled personnel are required to analyse the bands in mIEF. Further automating and standardizing the diagnostic methods via AI to identify abnormal Hbs would be a useful endeavor. In this study, we propose a novel approach for SCD diagnosis by integrating the high throughput capability of ResNet34 in image analysis, as a deep learning convolutional neural network, for the precise separation of Hb variants using mIEF. Initially, SCD blood samples were subjected to mIEF and the resulting patterns were then captured as digital images. The sensitivity and specificity of the mIEF analysis were 100% and 97.8%, respectively, with a 99.39% accuracy. Comparison with HPLC showed a strong linear correlation (R2 = 0.9934), good agreement with the Bland-Altman plot (average difference ± 1.96 SD, bias = 9.89%) and a 100% match with the DNA analysis. Subsequently, the mIEF images were then input into the ResNet34 model, pre-trained on a large dataset, for feature extraction and classification. The integration of ResNet34 with mIEF demonstrated promising results in terms of precision (90.1%) and accuracy in distinguishing between the various SCD conditions. Overall, the proposed method offers a more effective, automated, and reduced cost approach for SCD diagnosis, which could potentially streamline diagnostic workflows and mitigate the subjectivity and variability inherent in manual assessments.

Comparative study of sickling test, solubility test, and hemoglobin electrophoresis in sickle cell anemia

Abstract Background: Madhya Pradesh, a state in India, bears the highest number of sickle cell anemia (SCA) cases, particularly among its tribal communities. The diagnosis of suspected SCA cases involves utilizing several methods. The sickling test operates on the principle of hemoglobin S (HbS) polymerization upon deoxygenation. By contrast, the solubility test involves the reduction of HbS using sodium hydrosulfite, followed by precipitation of lysed red blood cells. Hemoglobin (Hb) electrophoresis identifies Hb variants based on their migration in an electric field. Our objective was to assess the efficacy of sickling and solubility tests as screening tools for detecting SCA, comparing them against capillary Hb electrophoresis, which is considered the gold standard. Materials and Methods: All individuals suspected of having SCA between 2022 and 2023 were enrolled in the study. Clinical information, peripheral blood smear analysis, sickling test, solubility test, and capillary Hb electrophoresis were conducted, and the results were compared. Results: Of 250 cases assessed, Hb electrophoresis identified 225 cases of SCA, resulting in a sickle cell disease to sickle cell trait (SCT) ratio of 1:1.36 and a male-to-female ratio of 1:1.33. The highest number of cases were observed in the age group from 21 to 30 years. Generalized weakness (77%) and abdominal pain (52%) were the most frequently reported symptoms. The sickling test demonstrated a sensitivity, specificity, and diagnostic accuracy of 91.5%, 72%, and 89%, respectively, compared with Hb electrophoresis. The solubility test yielded values of 76.5%, 68%, and 75% for sensitivity, specificity, and diagnostic accuracy, while peripheral smear analysis showed 36%, 25%, and 42%, respectively. Conclusion: The sickling test displayed superior sensitivity and diagnostic accuracy compared with the solubility test, with no significant disparity in specificity between these two methods. Notably, the solubility test exhibited a higher incidence of false-negative results for SCT. Therefore, the sickling test is the preferred screening method for SCA.

Comparison of Capillary Zone Electrophoresis with High-pressure Liquid Chromatography in the Evaluation of Hemoglobinopathies

The capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC) methods were compared in terms of HbA2 measurement for the assessment of hemoglobinopathies. CZE was compared with HPLC for the evaluation of patients without hemoglobinopathy (n=321), with β-thalassemia trait (n=113), and with common (HbD-Punjab, E, C, S/A, and S/S) and rare (HbS/D, O-Arap, Lepore, G-Coushata, Setif, Hamadan, Q-Iran, and H) variants (n=21). The reference range for HbA2 was determined by CZE. Among patients without hemoglobinopathy, the median (2.5th-97.5th percentiles) values were 97.4% (97.0-98.0%) and 97.5% (96.6-98.4%) for HbA (p=0.060) and 2.4% (1.6-3.0%) and 2.5% (1.6-3.1%) for HbA2 (p<0.001) by HPLC and CZE, respectively. The reference range for HbA2 was 1.6-3.1% by CZE. In the comparison of methods for HbA2, there was a constant error of 0.255 (confidence interval: 0.062-0.448) and bias of 0.10% (limit of agreement: 0.33-0.53), and higher values were obtained with CZE. A strong correlation was observed between the methods (r=0.782). Interrater agreement was almost perfect for clinical diagnosis (ϰ=0.911). The two methods detected and identified the common variants similarly. All rare variants, except HbH by HPLC and HbS/D by CZE, were detected as separate peaks by both methods. The two methods were in agreement regarding the preliminary identification of β-thalassemia patients. Different Hb variants were detected by both methods but with possible methodological interference for HbA2 measurements. CZE is a reliable and simple alternative for the evaluation of hemoglobinopathies. The standardization of HbA2 measurements should be prioritized as more techniques become available in routine laboratory practice.

Anesthetic Management of a Patient With Hemoglobin M Disease Undergoing Laparoscopic Uterine Myomectomy: A Case Report

Hemoglobin M (Hb M) is a group of abnormal Hb variants that form methemoglobin, which leads to cyanosis. Patients with Hb M appear cyanotic but are usually asymptomatic. Cyanosis with low peripheral oxygen saturation is unresponsive to oxygen therapy despite normal partial pressure of oxygen. As such, close attention should be paid during anesthesia. We report the first case of a Hb M patient undergoing laparoscopic uterine myomectomy under general anesthesia.

Chronic disease prevalence in a population with structural hemoglobin disorders undergoing diabetes diagnosis: A bayesian approach

BackgroundStructural disorders of hemoglobin are a group of rare and fatal genetic diseases that disrupt the transport and exchange of oxygen in the blood, causing tissue damage and ultimately leading to chronic conditions. The hemoglobin (Hb) S variant predominantly impacts individuals of Afro-descendant heritage. A significant concentration of the Afro-descendant population in Colombia, notably 12.5 %, is found in the city of Cali. Previous research has identified this city's structural hemoglobin disorders prevalence rate of 3.78 %. The aim of this study was to determine the prevalence of HbC, HbS, HbF, and HbA2 variants within a population who underwent HbA1c testing, as well as the prevalence of chronic diseases among patients with these hemoglobin alterations, at a high-complexity hospital in the city of Cali from 2015 to 2019. MethodsA descriptive observational study was conducted, involving a study population that comprised patients with both suspected and monitored diagnoses of diabetes. The cohort was selected from a high-complexity hospital in Cali. A total of 15,608 patients were included in the analysis, all of whom underwent HbA1C measurement through capillary electrophoresis, which also offers an indirect diagnosis of certain structural disorders of hemoglobin. Bayesian methods were employed for frequency analysis. ResultsAmong the 15,608 patients assessed, 63.6 % (n = 9920) were women. The overall prevalence of structural hemoglobin disorders was 1.98 % (n = 287, 95 % CI = 1.77 %–2.21 %). The co-occurrence of diabetes and kidney disease emerged as the most prevalent combination of pathologies observed in individuals with HbC, for both men and women across various age groups: 18–42 (58.3 % and 50.0 % respectively), 43–55 (50.0 % for both), 56–65 (50.0 % and 37.5 % respectively), and >65 years (66.7 % and 57.1 % respectively). ConclusionsThe observed prevalence of the studied variants exceeded 1 %, a threshold underscored by the World Health Organization (WHO) as epidemiologically significant. Among HbC and HbS-positive patients, the elevated prevalence of diabetes and kidney disease is a guiding factor in developing proactive prevention strategies.

Identification of Hb Lepore, Hb anti-Lepore, and α-globin gene triplications by long-read single-molecule real-time sequencing.

Hemoglobin (Hb) Lepore and Hb anti-Lepore are infrequent fusion gene variants that result from nonhomologous crossovers during meiosis. Conventional molecular testing methods may face challenges in identifying these variants. During Hb analysis using capillary electrophoresis, we encountered 6 cases with unusual Hb variants. Our aim was to identify the alterations in their globin genes. Gap-polymerase chain reaction (PCR), reverse dot-blot assay (RDB), Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), and long-read single-molecule real-time (SMRT) sequencing were used to confirm the presence of globin gene alterations. The routine thalassemia gene test kit using the gap-PCR and RDB techniques did not detect common gene variations. Direct sequencing failed to identify any known or unknown globin gene alterations. The MLPA analysis, however, revealed the possible presence of α-globin gene triplications as well as 2 types of fusion gene alterations. Further analysis using long-read SMRT sequencing accurately identified 3 rare gene variations: αααanti-3.7, Hb Lepore-Boston-Washington, and Hb anti-Lepore P-India. Conventional methods may overlook rare thalassemias or Hb variants. Long-read SMRT sequencing has the potential to identify breakpoints in fusion genes, demonstrating that it is a promising technique for detecting rare thalassemias.

Evaluation of the Premier Hb9210 instrument for HbA1c determination

Background: Glycated hemoglobin measurements are a valuable tool for long-term blood glucose monitoring and the diagnosis of diabetes. Its widespread use has been made possible due to the development of new analytical methods with improved performances and standardization with reference materials. The aim of the present study was to evaluate the Trinity Biotech Premier Hb9210 analyzer for the measurement of HbA1c. Methods: The precision was assessed using the CLSI EP-15A3 and EP-10A3 protocols. The latter was also used to investigate linearity, carryover, and linear drift. The comparison study was performed between Premier Hb910 and Tosoh HLC-723 G8 through Passing–Bablok regression and the Bland-Altman plot. The Fleiss Kappa index was used to assess the degree of agreement. The interference of Hb variants was investigated using samples with Hb variants S, C, D, E, J, and Seville. Results: Within-run and between-run imprecision fell between 0.37% and 1.16%. No statistically significant nonlinearity, carry-over, and/or drift were observed. The resulting regression line of the Passing–Bablok analysis was y = 0.00 + 1.00x. The Pearson correlation coefficient was 0.997. In the Bland–Altman plot, the relative bias was 0.01%. The overall Fleiss Kappa index was 0.9. No interference from hemoglobin variants was observed. Conclusion: The Premier Hb9210 demonstrated a high degree of automation, reproducibility, good agreement, minimal carry-over effect, and excellent linearity across the wide range of HbA1c levels commonly found in diabetic patients and was not influenced by Hb variants.