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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]

Objective: To report the diagnostic challenges of newborn screening for abnormal haemoglobins. Setting: Cord blood samples from 13 hospitals in southwest Jamaica taken in 2008–2019. Methods: Blood spots, collected from the umbilical cord, were analysed by high pressure liquid chromatography (HPLC) to reveal phenotypes for HbSS and HbCC, but genotype confirmation may require parental studies or gene sequencing. Such cases that were successfully traced were analysed in this follow-up study. Results: HPLC screening of 121,306 samples detected HbAS in 11,846 (9.8%), HbAC in 4508 (3.7%) and other electrophoretic abnormalities in 1090 babies. Among 101 previously unconfirmed cases, 34/90 (38%) with HPLC evidence of a HbSS phenotype had other genotypes, and 7/11 (64%) with a HbCC phenotype had other genotypes. Syndromes from the interaction of β thalassaemia occurred in 112 babies (85 with HbS, 27 with HbC) and of genes for hereditary persistence of fetal haemoglobin (HPFH) in 18 (12 with HbS, 6 with HbC). Variants other than HbS and HbC occurred in 270 babies, 16 in combination with either HbS or HbC, and 254 as traits. Most variants are benign even when inherited with HbS, although HbO Arab, HbD Punjab, or Hb Lepore Washington, which occurred in 6 cases, may cause sickle cell disease. Conclusions: Genes for β thalassaemia and HPFH are common in western Jamaica and when associated with HbS may present diagnostic challenges in newborns, as HbF and HbA2 have not reached diagnostic levels. Family and DNA studies may be necessary for genotype confirmation. [ABSTRACT FROM AUTHOR]

Key Content: The haemoglobinopathies encompass a complex collection of red blood cell disorders that are responsible for considerable morbidity and mortality in women and their unborn children.Sickle cell disease and the thalassaemias are the commonest haemoglobinopathies encountered in UK clinical practice.A consistent standard of care will enable women with haemoglobinopathies to have a pregnancy that is as safe as possible, with good outcomes and minimal long‐term effects on their health and the health of their babies.The most effective way to deliver a consistent standard of care for these women is via the multidisciplinary team (MDT). The MDT should include a haematologist, cardiologist, maternal medicine obstetrician, specialist midwife, reproductive medicine specialist and a nurse specialist.The care of these women, within the MDT, should start with pre‐conception advice and continue through their antenatal care, intrapartum support and finally, provide postnatal considerations including contraception advice. Learning Objectives: To understand the inheritance, incidence, detection and pathophysiology of the commonest haemoglobinopathies.To appreciate the role of pre‐conception advice and prenatal diagnosis in the management of women with a haemoglobinopathy.To appreciate the multidisciplinary team approach in managing women with these conditions. Ethical Issues: Prenatal diagnostic techniques can be used to diagnose an affected pregnancy; however, diagnosis after conception means families must address the option of terminating the pregnancy. This requires expert counselling to minimise long‐term sequelae.The definitive prenatal tests – chorionic villus sampling and amniocentesis – are both associated with a small risk of miscarriage.Non‐invasive free fetal DNA (ffDNA) tests that will minimise the risk of testing to the developing fetus are being developed, but use of these tests will still require expert counselling both before and after a test is taken. [ABSTRACT FROM AUTHOR]

A female patient aged 47 years presented with a hemoglobin A1c (HbA1c) level of 54.6%, as measured by ion-exchange high-performance liquid chromatography (HPLC), and a glucose level of 106 mg/dL. The HbA1c was re-evaluated using a turbidimetric inhibition immunoassay and found below the level of detection. Hemoglobinopathy testing led to the identification of a hemoglobin variant consistent with Hb Raleigh, in which a valine → alanine substitution on the beta chain effects a charge difference, resulting in coelution with HbA1c on HPLC and a spuriously high reading. Many Hb variants may interfere with HbA1c measurement and generate misleading results. The unique properties of Hb Raleigh may give rise to analytical errors when evaluating HbA1c using 2 different methods—molecular charge–based (eg, HPLC) and molecular structure–based (eg, immunoassay)—yielding diametrically opposed results. Consequently, recognition and diagnosis of this entity are essential in patients with Hb Raleigh, especially when monitoring long-term glucose control. [ABSTRACT FROM AUTHOR]

Background: Antenatal screening is vital to identifying couples at risk of having children with a clinically significant haemoglobinopathy. In Australia, immigration is increasing carrier incidence. Methods: A retrospective analysis was performed of full blood count, high-performance liquid chromatography and haemoglobin electrophoresis of women and their partners who underwent antenatal haemoglobinopathy screening over three years at a major NSW laboratory. Genetic testing results were included where available. Results: One thousand six hundred and twenty-eight women and 729 male partners were screened at a median gestation of 14 weeks. 8.2% of women had a clinically significant result, with a median 16-day interval to partner testing. In 35% of couples screened simultaneously, the partner did not require testing. Genetic confirmatory testing was performed in 65% of high risk couples. Conclusion: There was a significant delay to antenatal haemoglobinopathy screening for mothers, limiting time for genetic diagnosis, prenatal diagnosis and management of affected pregnancies. Screening should be performed earlier. Simultaneous couple testing is not cost-effective. [ABSTRACT FROM AUTHOR]

Consanguinity is a social behavior characterized by the arrangement of marriages between relatives. It coincides generally with the geographic distribution of recessive genetic diseases as it increases the likelihood of homozygosis and, consequently, the incidence of their pathologies in the population. In this pilot study, we assess the effect of inbreeding on the burden of hemoglobinopathies in Northern Morocco. From January 2016 to December 2018, 197 children born in the studied region to three ancestral generations and diagnosed with hemoglobinopathies were subject to investigation. The rate of consanguinity in the parents' generation of children with hemoglobinopathies was 50.25%, with first cousin marriages accounting for 68.69% of consanguineous unions (FI = 0.02). The corresponding rates in the general population, based on a sample of N = 900, were 29.67% and 82.02%, respectively. The marriages between first cousins are the most common among the other types of consanguineous unions. Our study propounds that consanguinity substantially contributes to the hemoglobinopathy burden in the studied region and has changed little over time. Refraining from consanguineous marriages and detecting couples at risk could contribute to the reduction of the incidence of genetic diseases in our country. [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]

The article presents a case study that involves an asymptomatic neonate with reduced peripheral oxygen saturations (SpO2), whereby the patient's father has a confirmed rare haemoglobinopathy, haemoglobin Titusville. It reports that Haemoglobin Titusville is a low-oxygen affinity haemoglobinopathy involving a single nucleotide change from G to A at codon 94 of the alpha globin gene.

Since 1993, following the National Thalassemia Major Prevention Program and an increase in immigration and interracial marriages, especially in southern Taiwan, the distribution of hemoglobinopathies may have changed. This study investigates the epidemiologic transition of hemoglobinopathies. We analyzed 1870 specimens collected between 2003 and 2012 in southern Taiwan, used gap-polymerase chain reaction and PCR-restriction fragment length polymorphism-based methods, and confirmed genotypes of hemoglobinopathies by DNA sequencing. We found a 91% reduction in the incidence of thalassemia major compared with samples from between 1986 and 1995. The most common genotypes of α-thalassemia and α Hb variants were the SEA type (69.4%) and Hb Quong Sze (1.54%). The most common genotypes of β-thalassemia and β Hb variants were IVS-II-654 (46.2%) and Hb E (2.2%), respectively. Compared with studies performed in different areas of and time intervals in Taiwan, a higher prevalence of -α3.7, Hb Quong Sze, and Hb E and a lower prevalence of the SEA type were found in this study. However, the SEA type remained the most common genotype observed. In addition, an increasing number of cases with an -α3.7 type carrier, Hb Quong Sze carrier, and Gγ(Aγδβ)° were identified following a peak of interracial marriages between 2003 and 2005, reflecting a regional difference and the impact of interracial marriage. In conclusion, global migration and international marriage have changed the distribution of hemoglobinopathies in Taiwan. A more comprehensive prenatal screening for new immigrants with a longer follow-up is warranted. [ABSTRACT FROM AUTHOR]

Hemoglobinopathies are caused by point mutation in globin gene that results in structural variant of hemoglobin. While 7 % of world populations are carrier of hemoglobinopathies, the prevalence of the disease varies between 3 to 17 % across different population groups in India. In a diagnostic laboratory, alkaline gel electrophoresis and cation exchange-based HPLC (CE-HPLC) are most widely used techniques for characterization of hemoglobin variants. In the above methods, the differential surface charge of hemoglobin molecule in variants is exploited for their characterization. Sometime, co-migration of variants in gel electrophoresis and co-elution or elution with unknown retention time in automated CE-HPLC might lead to ambiguity in the analysis of hemoglobinopathies. Under such circumstances, it is necessary to use other analytical methods that provide unambiguous results. Mass spectrometry-based proteomics approach and DNA sequence analysis are examples of such alternative methods. In the present study, liquid chromatography coupled to mass spectrometry has been used for three commonly observed variants in India, e.g., HbE, HbQ India and HbD Punjab that appeared with inappropriate results in the conventional analysis. A customized hemoglobin variant database has been used in the mass spectrometry-based analysis of those three variants. Mass spectrometry-based proteomics approach was used to analyze above variant sample accurately. [ABSTRACT FROM AUTHOR]

Background HbA1c is used in the diagnosis and monitoring of diabetes mellitus (DM). Interference from hemoglobin variants is a well-described phenomenon, particularly with HPLC-based methods. While immunoassays may generate more reliable HbA1c results in the presence of some variants, these methods are susceptible to negative interference from high concentrations of HbF. We report a case where an accurate HbA1c result could not be obtained by any available method due to the presence of a compound hemoglobinopathy. Methods HbA1c was measured by HPLC, immunoassay, and capillary electrophoresis. Hemoglobinopathy investigation consisted of a CBC, hemoglobin fractionation by HPLC and electrophoresis, and molecular analysis. Results HbA1c analysis by HPLC and capillary electrophoresis gave no result. Analysis by immunoassay yielded HbA1c results of 5.9% (Siemens DCA 2000 +) and 5.1% (Roche Integra), which were inconsistent with other markers of glycemic control. Hemoglobinopathy investigation showed HbC with the hereditary persistence of fetal hemoglobin-2 Ghana deletion. Conclusion Reliable HbA1c results may be unobtainable in the presence of some hemoglobinopathies. HPLC and capillary electrophoresis alerted the laboratory to the presence of an unusual hemoglobinopathy. Immunoassays generated falsely low results without warning, which could lead to missed diagnoses and under treatment of patients with DM. [ABSTRACT FROM AUTHOR]

Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman’s rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to study the difference in Hb A1c between patients with normal hemoglobin and hemoglobin traits. A total of 431 patients were studied. There was positive correlation with age in patients with normal chromatograms only. No correlation was seen in Hb E trait or beta thalassemia trait. No significant difference in Hb A1c of patients with normal chromatograms and patients with hemoglobin traits was seen. There is no interference by abnormal hemoglobin in the detection of A1c by high performance liquid chromatography. This method cannot be used for detection of A1c in compound heterozygous and homozygous disorders. [ABSTRACT FROM AUTHOR]

The thalassemias are among the most common monogenic diseases worldwide, a national health burden in India. There are estimated 7500–12,000 babies born with β-thalassemia major (β-TM) every year in this country. Couples who are at-risk of having children with hemoglobin (Hb) disorders desired to have the option of avoiding the birth of an affected child by prenatal diagnosis (PND). Thus, the prenatal women are a highly important target group for carrier screening and preventing the birth of thalassemic children in the country. The present study was conducted among 20,883 pregnant women, irrespective of gravida and duration of pregnancy, from the prenatal clinic of Nilratan Sarkar (NRS) Medical College & Hospital, Kolkata, West Bengal, India, from February 2009 to November 2012. Thalassemia carrier status was assessed by high performance liquid chromatography (HPLC) along with red blood cell (RBC) indices. Husbands of all thalassemia carrier women were advised and persuaded to undergo screening for hemoglobinopathies. The couples were counseled to undergo PND if both of them were detected to be thalassemia carriers. The data were statistically analyzed to evaluate the efficacy of this procedure. [ABSTRACT FROM AUTHOR]

Background The World Health Organization and the American and Canadian Diabetes Associations approved HbA1c > 6.5% as diagnostic for type 2 diabetes mellitus (T2DM). Hb variants and/or their chemically modified species can interfere with HbA1c measurements. We recently described a patient with Hb Wayne trait who was misdiagnosed with T2DM based on falsely elevated HbA1c. Hb Wayne is a clinically silent variant that exists as two isoforms: Hb Wayne I (Asn 139) and Hb Wayne II (Asp 139). Methods Hemoglobinopathy investigation was performed by HPLC (Bio-Rad VARIANT-II), alkaline and acid electrophoresis (Sebia Hydrasis2), capillary zone electrophoresis (Sebia CAPILLARYS2™) and DNA sequencing. HbA1c was measured by five methods. Results Hb Wayne eluted as two small fractions with retention times of 1.0 and 1.46 min on the HPLC (Bio-Rad VARIANT-II). Alkaline gel and capillary electrophoresis showed two small bands migrating faster than HbA. Hb Wayne generated spuriously high results on the Bio-Rad VARIANT-II Turbo 2.0, no results on the Tosoh G8, and did not interfere with either the Sebia CAPILLARYS2™ or immunoassays from Roche (tinaquant) and Siemens (Bayer DCA2000 +). Based on the Hb Wayne HPLC profile of 3 patients, an algorithm was developed to facilitate its detection, which identified 9 additional patients with Hb Wayne trait. Conclusions We characterize Hb Wayne by chromatographic and electrophoretic techniques and show the effect of Hb Wayne on five common HbA1c methodologies. We developed a quality assurance tool to assist in detecting Hb Wayne trait during HbA1c analysis on the Bio-Rad VARIANT-II™ Turbo 2.0. [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]

More than 1000 hemoglobin (Hb) variants have been identified. Hb Kirksey, a rare Hb variant involving mutation at codon 94 of α2-globin, is associated with low oxygen affinity. To our knowledge, there is no case report on Hb Kirksey in the literature, and, accordingly, the clinical features of patients with Hb Kirksey are currently unknown. We report here the case of a neonate who presented with asymptomatic low oxygen saturation on pulse oximetry (SpO2) just after birth, together with clinical analysis of the sister and cousin. Based on the presentations, Hb Kirksey does not seem to be associated with clinical abnormalities. Discrepancy between SpO2 and partial pressure of arterial oxygen (PaO2) detected on arterial blood gas analysis provided a clue to the diagnosis. Hb variants should be suspected and arterial blood gases should be measured in pediatric cases of unexplained low SpO2. [ABSTRACT FROM AUTHOR]

We report the case of a 56-year-old Caucasian woman in whom hemoglobinopathy screening was triggered following an aberrant Hb A1canalysis. Preliminary diagnosis of the hemoglobin (Hb) variant was obtained through cation exchange high performance liquid chromatography (HPLC) and gel electrophoresis. DNA analysis confirmed the presence of Hb J-Amiens [β17(A14)Lys→Asn;HBB: c.[54G > C or 54G > T)]. However, an unbalanced ratio between wild type and mutant signal after direct sequencing and a lower than expected percentage of this Hb variant led to the suggestion of a mosaic expression. Furthermore, different methods [capillary zone electrophoresis (CZE), cation exchange HPLC and boronate affinity] were tested to study the possible interference of this variant with Hb A1cmeasurements. These investigations showed a clinically relevant difference between the methods tested. Hb A1canalysis may lead to the discovery of new Hb variants or mosaicism for previously described Hb variants. This may have genetic consequences for the offspring of carriers and brings about the question of partner testing. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 13-year-old Japanese girl with hemoglobin Seattle (Hb-Seattle), an inheritable hemoglobinopathy. Topics include low peripheral capillary oxygen saturation (SpO2), unstable Hb complex determined by positive isopropanol test, and quantification of fetal Hb (HbF).

Key Clinical Message The relevance of this case lies in the extensive diagnostic workup that can be avoided with proper laboratory evaluation of relatively unsophisticated tests. [ABSTRACT FROM AUTHOR]