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Hemoglobin disorders are among the most common genetic diseases worldwide. Molecular diagnosis is helpful in cases where the diagnosis is uncertain and for genetic counseling. Protein‐based diagnostic techniques are frequently adequate for initial diagnosis. Molecular genetic testing is pursued in some cases, particularly when a definitive diagnosis is not possible and especially for the purpose of assessing genetic risk for couples wanting to have children. The expertise available in the clinical hematology laboratory is essential for the diagnosis of patients with hemoglobin abnormalities. Initial diagnoses are made using protein‐based techniques such as electrophoresis and chromatography. Based on these findings, genetic risk to an individual's offspring can be assessed. In the setting of β‐thalassemia and other β‐globin disorders, coincident α‐thalassemia may be difficult to diagnose, which can have potentially serious consequences. In addition, unusual forms of β‐thalassemia caused by deletions in the β‐globin locus cannot be definitively characterized using standard techniques. Molecular diagnostic testing has an important role in the diagnosis of hemoglobin disorders and is important in the setting of genetic counseling. Molecular testing also has a role in prenatal diagnosis to identify fetuses affected by severe hemoglobinopathies and thalassemias. [ABSTRACT FROM AUTHOR]

Hemoglobinopathies are the most common monogenic disorders in the world with an ever increasing global disease burden each year. As most hemoglobinopathies show recessive inheritance carriers are usually clinically silent. Programmes for preconception and antenatal carrier screening, with the option of prenatal diagnosis are considered beneficial in many endemic countries. With the development of genetic tools such as Array analysis and Next Generation Sequencing in addition to state of the art screening at the hematologic, biochemic and genetic level, have contributed to the discovery of an increasing number of rare rearrangements and novel factors influencing the disease severity over the recent years. This review summarizes the basic requirements for adequate carrier screening analysis, the importance of genotype–phenotype correlation and how this may lead to the unrevealing exceptional interactions causing a clinically more severe phenotype in otherwise asymptomatic carriers. A special group of patients are β‐thalassemia carriers presenting with features of β‐thalassemia intermedia of various clinical severity. The disease mechanisms may involve duplicated α‐globin genes, mosaic partial Uniparental Isodisomy of chromosome 11p15.4 where the HBB gene is located or haplo‐insufficiency of a non‐linked gene SUPT5H on chromosome 19q, first described in two Dutch families with β‐thalassemia trait without variants in the HBB gene. [ABSTRACT FROM AUTHOR]

Introduction: Hemoglobinopathies are major public health problems worldwide. Accurate laboratory diagnosis of the carrier is essential, which includes initial screening, Hb analysis, and DNA analysis. For the first time, we have developed a single‐tube quality control (QC) sample for these laboratory tests. Methods: The QC sample was made from a lyophilized mixture of the stabilized hemolysate with carbon monoxide saturation and the white blood cells of known thalassemia mutations. Homogeneity and stability were examined by Hb and DNA analyses on day 0 and every month for 12 months, at room temperature, 4°C, and −20°C. A preliminary proficiency testing (PT) program for hemoglobinopathies using this single QC material was developed. Results: Hemoglobin (Hb) and DNA analyses of a single‐tube QC sample demonstrated satisfactory results of Hb analysis for at least five months and DNA analysis for at least one year of storage at −20°C. The results obtained from a preliminary PT program on five expert laboratories confirmed that a single tube QC sample prepared could be used as a PT item with various Hb and DNA analyses methods. Conclusion: A single lyophilized control sample has been generated for use in hemoglobinopathies' internal and external quality control program. Unlike other available control materials, which are used for individual testing, a single‐tube QC sample generated can be used to control the pre‐analytical and analytical processes of both Hb and DNA analyses and is suitable for use in the PT program of hemoglobinopathies. [ABSTRACT FROM AUTHOR]

The article focuses on the impact of Voxelotor, an oral sickle hemoglobin inhibitor, on the quantitation of HbS levels in a patient with sickle cell disease. Topics include the patient's clinical presentation, the challenges in accurately quantifying HbS levels using high-performance liquid chromatography (HPLC) due to Voxelotor treatment, and the importance of providing information about the patient's drug treatment to ensure proper laboratory test interpretation.

Introduction: Hemoglobin (Hb) analysis is a key testing for diagnosis of hemoglobinopathies. Accurate analysis, interpretation of results, and genetic risk assessment are important. We report on 8 years of the proficiency testing (PT) program for hemoglobinopathies in Thailand. Methods: Laboratory participants were required to test two simulated PT items in each cycle using capillary electrophoresis, one was a husband and another was his pregnant wife. Related hematological parameters were provided. The participants also provide interpretation and evaluate the risk of having three severe thalassemia diseases in an expected fetus. Three cycles were operated per year in accordance with the ISO17043 and ISO13528 guidelines. A total of 84 laboratories throughout Thailand were participated. Results: A total of 24 PT cycles were performed during 2012‐2019. Most participants had Excellent performance for the PT items with normal, β‐thalassemia trait, hemoglobin E trait, hemoglobin E trait with α‐thalassemia, and Hb H disease. However, when the PT items with homozygous Hb E and Hb E‐β‐thalassemia were tested, an increase in a Needs improvement performance was noted. From 24 PT cycles, the performance with Excellent, Good, Fair, and Needs improvement was ranging from 10.5%‐95.8%, 0%‐11.3%, 0%‐77.2%, and 2.3%‐37.0%, respectively. Conclusion: Most participants have proven their performance to be reliable and demonstrated their abilities to provide interpretation and genetic risk assessment on most of the PT items. For complex thalassemia however, a need to improve the interpretation and risk assessment skills is required which is essential for effective prevention and control of severe thalassemia diseases in Thailand. [ABSTRACT FROM AUTHOR]

Introduction: The hemoglobinopathies pose a significant health burden in India. Apart from the β thalassemias and sickle cell disorders, α thalassemias and structural hemoglobin variants are also common. Here we have reviewed the phenotypic and molecular diversity of hemoglobinopathies encountered at a referral center in western India over a period of 15 years. Materials and Methods: Screening for hemoglobinopathies was done using HPLC and cellulose acetate electrophoresis. Molecular characterization was done using Covalent Reverse Dot Blot Hybridization (CRDB), Amplification Refractory Mutation System (ARMS), GAP PCR and direct DNA sequencing. Results: The study includes 31 075 individuals who were referred for diagnosis of hemoglobinopathies and prenatal diagnosis. Of these 14 423 individuals showed various hemoglobin abnormalities. Beta genotyping in 5615 individuals showed the presence of 49 β thalassemia mutations. 143 β thalassemia heterozygotes had normal or borderline HbA2 levels. We identified three δ gene mutations (HbA2 Pellendri, HbA2 St.George, HbA2 Saurashtra) in β thalassemia heterozygotes leading to normal HbA2 levels. The commonest defects among the raised Hb F determinants were Gγ(Αγδβ)0 Indian inversion and the HPFH‐3 Indian deletion. A total of 312 individuals showed the presence of α thalassemia, of which 12.0% had a single α gene deletion (−α/αα). HbH disease was identified in 29 cases with 10 different genotypes. Alpha globin gene triplication was seen in 2.1% of β thalassemia heterozygotes with a thalassemia intermedia phenotype. Seven unusual α chain variants and eight uncommon β chain variants were identified. Conclusion: The repertoire of molecular defects seen in the different globin genes will be valuable for management and control of these disorders both in India as well as in other countries where there is a huge influx of migrant populations from India. [ABSTRACT FROM AUTHOR]

Abstract: The hemoglobinopathies, as a group, are one of the most common serious monogenic diseases in the world. An accepted and widely adopted approach to reduce the number of new cases involves carrier‐screening programs, with the option of prenatal diagnosis (PND) or preimplantation diagnosis (preimplantation genetic testing for monogenic disease, PGT‐M) for carrier couples. The aim of PND is to provide an accurate result as early in pregnancy as possible, which necessitates prior identification of the parental disease‐causing mutations, as well as safe and timely biopsy of fetal material. PGT‐M aims to characterize the genetic status of in vitro fertilized embryos during assisted reproductive technology (ART), in a few cells biopsied from oocytes/zygotes or embryos, in order to initiate an unaffected pregnancy. Another application of PGT‐M is preimplantation genetic diagnosis for human leukocyte antigen (PGD‐HLA), which, in addition to identifying unaffected embryos, also characterizes the embryos that are HLA compatible with an existing affected child requiring a hemopoietic stem cell transplantation (HSCT). This review outlines the current practices related to these procedures, with emphasis on the aspects related to laboratory techniques. Finally, future prospects related to developments in noninvasive prenatal diagnosis are discussed. [ABSTRACT FROM AUTHOR]

Introduction Differentiation of homozygous hemoglobin (Hb) E with and without α0-thalassemia is subtle on routine hematological ground. We examined in a large cohort of homozygous Hb E if the level of Hb A2 is helpful. Methods A total of 592 subjects with homozygous Hb E were recruited from ongoing thalassemia screening program. Additionally, five couples at risk of having fetuses with Hb Bart's hydrops fetalis who were homozygous Hb E were also investigated. Hb analysis was performed using capillary electrophoresis system. Globin genotypes were defined by DNA analysis. Results Subjects were classified into four groups including pure homozygous Hb E (n=532), homozygous Hb E/α0-thalassemia (n=48), Hb Constant Spring EE Bart's disease (n=8), and Hb EE Bart's disease (n=4). The levels of Hb A2 were found, respectively, to be 4.97±0.69, 6.64±1.02, 4.86±0.87, and 7.60±1.04%. Among five couples at risk, α0-thalassemia was identified in three subjects with Hb A2>6.0%. Conclusions Increased Hb A2 level is a useful marker for differentiation of homozygous Hb E with and without α0-thalassemia. This should lead to a significant reduction in number of referral cases of homozygous Hb E for molecular testing of α0-thalassemia in routine practice. [ABSTRACT FROM AUTHOR]

Introduction Capillary zone electrophoresis (CZE) at alkaline pH is one of the techniques used for hemoglobinopathy screening. In this study, an evaluation of the performance of a lower throughput CZE instrument, the Sebia Minicap Flex Piercing system, for this purpose is reported for the first time. Methods The analytical performance of the Sebia Minicap Flex Piercing system was evaluated. Furthermore, a method comparison between the Sebia Minicap Flex Piercing and two HPLC methods, that is, the Bio-Rad Variant Classic™ and the Bio-Rad D-10™ systems was performed by measuring samples with and without clinically relevant hemoglobin disorders. Results The analytical performance was acceptable for the determination of HbA, HbA2, HbS, and HbF, with an imprecision ≤2.0%. Method comparison showed a linear correlation for HbA2, HbF, and HbS measurements. Clinical concordance was acceptable when comparing CZE and HPLC. Conclusions Lower throughput CZE using the Sebia Minicap Flex Piercing can be used for precise and accurate first line screening and follow-up of hemoglobinopathies. [ABSTRACT FROM AUTHOR]

Introduction: Phenotype studies still occupy a key position in the diagnosis of hemoglobin (Hb) disorders. Material and Methods: In addition to the conventional methods for diagnosis of Hb disorders which are mostly based on differences in charge of the Hb molecules, some progresses have been brought by studying other properties of the globin chains. Among those, difference in hydrophobicity that may be investigated by reversed-phase HPLC (RP-HPLC) discriminates between variants displaying identical charges. Results: In this study, we show how an update of this method allows to recognize an α-chain variant from a γ-chain variant, a problem frequently during neonatal screening. We illustrate that RP-HPLC may also unravel unclear phenotypes which are modified by the presence of an additional variant not detected by the conventional methods, and help to characterize rare mutants. Also we show that it allows a clear distinction between variants with identical electrophoretical charges as exemplified by Hb Lepore Boston-Washington and Lepore Baltimore. Conclusions: In view of our results, RP-HPLC is a technique that needs to be used as a second step in the general strategy for a correct characterization of Hb variants. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Potential pithfalls in the diagnosis of Hb Handsworth in areas with high prevalence of Hb S.," by S. Zadjali and colleagues in the 2014 issue.