Rare Hb Variants Research Articles

Coinherited Hemoglobin Lansing-Ramathibodi/Southeast Asian Deletional α0-thalassemia and Hemoglobin E Causing Falsely Low Oxygen Saturation on Pulse Oximetry

OBJECTIVE Hemoglobin (Hb) variants resulting from mutations in globin genes and leading to qualitative abnormalities of globin proteins can result in a spectrum of clinical presentations. Herein we describe a case of a 10-year-old boy with an Hb variant, Hb Lansing-Ramathibodi (HBA1:c.264C>G, codon 87 His>Gln), who was incidentally found to have low pulse oximetry oxygen saturation readings (low SpO2). Laboratory investigations revealed mild microcytic anemia. Arterial blood gas showed normal partial pressure of oxygen (PaO2) and arterial oxygen saturation (SpO2) values, indicating an oxygen saturation gap. Subsequent Hb analysis identified an abnormal peak, prompting further molecular studies which confirmed the coinheritance of Hb Lansing-Ramathibodi, Southeast Asian deletional α0-thalassemia and the Hb E trait. The patient’s mother, carrying the Hb Lansing-Ramathibodi and Hb E traits without Southeast Asian deletional α 0-thalassemia, was asymptomatic. This case underscores the importance of identifying and characterizing rare Hb variants presenting with an oxygen saturation gap for informed clinical management and genetic counseling. KEYWORDS alpha-thalassemia, coinheritance, hemoglobin Lansing- Ramathibodi, low SpO2, oxygen saturation

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.

Clinical and haematological characteristics of 38 individuals with Hb G-Makassar in Malaysia.

Haemoglobin (Hb) G-Makassar is a rare Hb variant. It presents a diagnostic challenge as it imitates sickle Hb (Hb S) in standard electrophoresis and high-performance liquid chromatography assays requiring DNA analysis to confirm diagnosis. Both have point mutations in codon 6, exon 1 in the β-globin (HBB) gene with different pathogenicities. This study describes the clinical phenotype, haematology and genotype of Hb G-Makassar. Clinical and laboratory data of 38 cases of Hb G-Makassar over 8 years were analysed. Hb G-Makassar was confirmed by a direct sequencing of HBB gene and co-inheritance of α-thalassaemia determined through multiplex gap-PCR and multiplex Amplification Refractory Mutation System polymerase chain reaction. All cases were Malays, predominantly from Terengganu (n=20, 52.6%). There were 14 (36.8%) males and 24 (63.2%) females with median age of 25 years. Majority (n=33, 86.8%) had features of thalassaemia trait with mean±SD for Hb, mean cell volume (MCV) and mean cell haemoglobin (MCH) as 13.21g/dL±1.69, 73.06±4.48fL and 24.71±1.82pg, respectively. None had evidence of haemolysis or thromboembolic complications. Six genotypes were identified; ßG-Makassar/ß,αα/αα (n=19, 50.0%), ßG-Makassar/ßE,αα/αα (n=4, 10.5%), ßG-Makassar/ßNewYork,αα/αα (n=1, 2.6%), ßG-Makassar/ß,αα/-α (n=11, 28.9%), ßG-Makassar/ß,αα/αAdanaα (n=2, 5.3%) and ßG-Makassar/ß,αα/-SEA (n=1, 2.6%). The ßG-Makassar/ß,αα/αα showed that features of thalassaemia trait with mean±SD for Hb, MCV and MCH were 13.74g/dL±2.40, 76.18±6.02fL and 25.79±2.41pg, respectively. This is the largest study reporting a significant number of Hb G-Makassar in Malaysia. Although the mutation is similar to Hb S, the phenotype is benign.

Third-Generation Sequencing as a New Comprehensive Technology for Identifying Rare α- and β-Globin Gene Variants in Thalassemia Alleles in the Chinese Population.

Identification of rare thalassemia variants requires a combination of multiple diagnostic technologies. To investigate a new approach of comprehensive analysis of thalassemia alleles based on third-generation sequencing (TGS) for identification of α- and β-globin gene variants. Enrolled in this study were 70 suspected carriers of rare thalassemia variants. Routine gap-polymerase chain reaction and DNA sequencing were used to detect rare thalassemia variants, and TGS technology was performed to identify α- and β-globin gene variants. Twenty-three cases that carried rare variants in α- and β-globin genes were identified by the routine detection methods. TGS technology yielded a 7.14% (5 of 70) increment of rare α- and β-globin gene variants as compared with the routine methods. Among them, the rare deletional genotype of -THAI was the most common variant. In addition, rare variants of CD15 (G>A) (HBA2:c.46G>A), CD117/118(+TCA) (HBA1:c.354_355insTCA), and β-thalassemia 3.5-kilobase gene deletion were first identified in Fujian Province, China; to the best of our knowledge, this is the second report in the Chinese population. Moreover, HBA1:c.-24C>G, IVS-II-55 (G>T) (HBA1:c.300+55G>T) and hemoglobin (Hb) Maranon (HBA2:c.94A>G) were first identified in the Chinese population. We also identified rare Hb variants of HbC, HbG-Honolulu, Hb Miyashiro, and HbG-Coushatta in this study. TGS technology can effectively and accurately detect deletional and nondeletional thalassemia variants simultaneously in one experiment. Our study also demonstrated the application value of TGS-based comprehensive analysis of thalassemia alleles in the detection of rare thalassemia gene variants.

Pitfalls in Estimation of Glycosylated Hemoglobin

Hemoglobin (Hb) Hope is a rare Hb variant which is clinically silent but causes spuriously high glycated hemoglobin (HbA1c). We report a case of a 45-year-old gentleman, planned for elective total hip replacement, who presented with very high HbA1c with normal blood glucose and fructosamine levels. With the suspicion of erroneous HbA1c, an Hb electrophoresis was done, and he was found to have a rare hemoglobin variant called Hb Hope. We also reviewed almost all case reports of Hb Hope variant causing spuriously high HbA1c levels from India.

Unexpected HbA1c results in the presence of three rare hemoglobin variants

Hemoglobin (Hb) variants, characterized by structural abnormalities in the globin chains, are among the most common inherited disorders. It has been shown that Hb variant remains an important cause of erroneous HbA1c results. Thus, it is important to be aware of the extent of the interference of each Hb variant encountered to avoid reporting unreliable results. However, the effects of many types of Hb variants on the measurement of HbA1c remain unclear. Here, we describe three rare Hb variants, Hb J-Tashikuergan [HBA2: c.59 C > A], Hb Pyrgos [HBB: c.251G > A], and Hb Hope [HBB: c.410 G > A], which lead to extremely high values (>25%) determined by Variant II Turbo 2.0. We further investigated their effects on HbA1c measurement by an HPLC system (Bio-Rad D100), a CE system (Sebia Capillarys 3 TERA), a boronate affinity chromatography system (Premier Hb9210), and an immunoassay method (Roche Diagnostics), and found that these Hb variants severely interfered with HbA1c measurement by Variant II Turbo 2.0 and Bio-Rad D100. This study demonstrates that patients with abnormally high HbA1c levels should be highly suspected of carrying Hb variants. When the HbA1c results are considered unreliable, other indicators such as glycated albumin may be a possible alternative to HbA1c in diabetic patients.

False positive testing for sickle hemoglobin in a blood donor with mild erythrocytosis and hemoglobin Geldrop St. Anna

Solubility testing for sickle hemoglobin is commonly performed to identify blood suitable for patients with sickle cell disease. A 32-year-old Caucasian male blood donor’s unit screened positive for sickle hemoglobin via solublity testing (Streck). As the donor was considered low risk for being positive for hemoglobin S (HbS), he self-referred to hematology for further evaluation. Testing with hemoglobin electrophoresis revealed the patient to be negative for HbS; however, 42 % fetal hemoglobin (HbF) was noted. Since this was higher than typically seen in hereditary persistence of HbF, deoxyribonucleic acid (DNA) sequencing of hemoglobin (Hb) was ordered through a referral laboratory. Hb gene sequencing revealed the patient to be heterozygous for Hb Geldrop St. Anna, a rare Hb variant. This variant has previously been shown to migrate in the HbF region with alkaline electrophoresis. The workup demonstrated that the oxygen dissociation curve was left-shifted consistent with slightly increased oxygen affinity of this variant. The patient’s hematocrits (Hct) from his past donations were 53 % and 54 % about two years apart and his Hct at his hematology evaluation was 53 %. This report describes the first case of Hb Geldrop St. Anna in the United States and was associated with a false positive HbS screen. This Hb variant is considered to be benign and has an increased oxygen affinity that is associated with mild erythrocytosis. The donor was allowed to continue donating blood products.

A Fast-Moving Hemoglobin, Hb J-Bangkok: A Case Study from a Single Referral Center in Malaysia

Fast-moving hemoglobins (Hbs) are a group of rare Hb variants that have a higher anodal electrophoretic mobility than Hb A on alkaline gel electrophoresis. Hb J-Bangkok (HBB: c.170G>A), a member of...

Dapson Tedavisine Bağlı Hemoliz Görülen Bir Hastada Hemoglobin D Saptanması

Dear Editor,Several mutations occur in the genes that encode globin chains which are a part of hemoglobin (Hb) structure. Such mutations give rise to formation of different hemoglobin variants.1 One of these hemoglobin variants (Hb C, D, E, F and S) is Hb D [β 121 Glu→Gln (GAA→CAA)]. Hb D occurs in 0.2% in Turkey.2 Molecular analysis has revealed many types of Hb D. Hb D-Los Angeles or Hb D-Punjab is the most common type.3 Clinically, heterozygous types of Hb D do not produce any hematological manifestations. However, mild-to-moderate cases of hemolysis have been rarely reported in conjunction with its homozygous forms.4 In this study, we present a case of hemolysis due to dapsone theraphy in coexistence with Hb D. A 17-year-old female patient who had been on colchicin treatment for Behçet’s disease for the last 3 years presented to the rheumatology department with persistent painful sores in her mouth. Following assessment of the patient, treatment with dapsone 50 mg tablets, three times daily was started by the rheumatology department. Two months after initiation of medical treatment, the patient presented to the hematology department with complaints of pallor, chills and fatigue. Her diagnostic work-up showed the following: Hb: 11.2 g/dL (11.9-14.6), MCV: 92.8 fL (81.8-95.5), PLT: 307 x 10³/uL (173-390), reticulocyte count: 264.5 x 103/uL (17-63.8), reticulocyte%: 7.09%, LDH: 367 U/L (0-279), total bilirubin: 2.7 mg/dL (0.1-1.5), indirect bilirubin: 1.5 mg/dL (0.08-1.1) and haptoglobulin< 30 mg/dL (30-200). Peripheral smear showed the presence of spherocytes and fragmented red blood cells. Direct and indirect Coombs tests were negative. Papain antibody and glucose 6 phosphate dehydrogenase (G6PD) tests were negative. Her laboratory values before dapsone therapy were as follows: Hb: 14.2 g/dL, MCV: 85.2 fL, PLT: 309 x 10³/uL. Initially, hemolytic anemia induced by dapsone was considered as possible diagnosis and dapsone treatment was discontinued. Laboratory work-up after three weeks showed a reticulocyte count of 125.6 x 10³/uL, % reticulocyte of 3.49%. These results prompted a request for hemoglobin electrophoresis based on a preliminary diagnosis of thalassemia. Hb D was found as 41.65% (Figure 1). Moleculer genetic test (DNA analysis) was found to be Hb D-Los Angeles [c.3646>C(p.E122Q)(p.Glu.122Gln)(Heterozygous)]. Hemoglobin electrophoresis was performed from the blood sample of her father and revealed Hb D of 88.13% and HbA2 of 3.91%. Her father was diagnosed with beta-thalassemia minor and Hb D. Drugs are a rare cause of hemolytic anemia. Dapsone is known to cause oxidative hemolysis. This situation has been reported to result from the direct toxic effect of a hydroxlamine derivative formed by N-hydroxylation to erythrocytes.5 Hemoglobin electrophoresis was performed for the patient during follow-up due to persistent hemolysis and a rare Hb variant was detected. This was a surprising finding for us, the physicians who were following the patient because her previous hemogram and biochemical analyses were not suggestive of thalassemia. Thus, we were facing two rare conditions at the same time: drug-induced hemolysis and Hb D.As a result; coexistence of hemolysis due to dapsone and Hb D is a rare condition. Since Hb D was found to be heterozygous in the patient, we think that this condition did not have clinical effect on hemolysis. To the best of our knowledge, this is the first case in which Hb D is detected in a patient with hemolysis due to dapsone.

Effect of hemoglobin N Baltimore on HbA1c measurement in six methods

The presence of hemoglobin variants can adversely affect the accuracy of some HbA1c methods depending on the variant. We examine the analytical interference from a rare Hb variant (Hb N Baltimore) with six different HbA1c methods using various method principles: two immunoassays methods (Tina-quant® HbA1c Gen et DCA Vantage), three high-performance liquid chromatography methods (G8 HPLC, Variant II Turbo A1c 2.0 et Variant II Dual kit), and one capillary-electrophoresis method (Capillarys Hb A1c kit). Hb N Baltimore can adversely affect determination of HbA1c levels. An underestimation of HbA1c level is observed with the chromatographic methods included in this study and no HbA1c result can be obtained with the capillary-electrophoresis method. Inversely, limited impact is observed with the immunoassays methods. The presence of an hemoglobin variant should be suspected when inconsistencies are observed between a patient's home blood glucose monitoring and laboratory-measured HbA1c. In these situations additional testing should be carried out using a test based on a different analytical method.

Severe Drug-Induced Hemolysis in a Patient with Compound Heterozygosity for Hb Peterborough (HBB: c.334G>T) and Hb Lepore-Boston-Washington (NG_000007.3: g.63632_71046del)

Unstable hemoglobins (Hbs) are often overlooked in the differential diagnoses of drug-induced hemolysis. Hb Peterborough [β111(G13)Val→Phe; HBB: c.334G>T] is a rare unstable Hb variant, predominantly found in individuals of Italian descent, due to a structural defect involving a single amino acid substitution (phenylalanine for valine at position 111 of the β-globin chain). Unstable Hb variants are often inherited in the heterozygous state with Hb A (α2β2) and rarely in compound heterozygosity with other Hb variants. The presence of another variant Hb often alters the phenotype, occasionally resulting in more severe disease. Using a combination of molecular techniques; multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing, we identified a compound heterozygosity for Hb Peterborough and Hb Lepore-Boston-Washington (Hb LBW) [δ87, β116; NG_000007.3: g.63632_71046del] in a middle-aged gentleman with a history of chronic microcytic anemia and splenomegaly, presenting with severe drug-induced hemolysis, which was managed conservatively. The clinical history and presentation reflect the dual pathology due to the presence of two variant Hbs and their associated phenotypes. In this article, we discuss the phenotype resulting from the interaction of Hb Peterborough and Hb LBW and emphasize the importance of molecular testing in the diagnosis of rare Hb variants.

Precision of CAPILLARYS 2 for the Detection of Hemoglobin Variants Based on Their Migration Positions.

In this report, we evaluated utility of the capillary electrophoresis (CE) migration position of the CAPILLARYS 2 CE instrument. The precision of this x-axis number was determined on a selection of common hemoglobin (Hb) variants (Hb S, Hb C, Hb D-Punjab, Hb E, Hb Hope), and the reproducibility of this number was evaluated by comparing the results obtained by two large reference laboratories on 81 Hb variants. Additionally, the CE migration position is given for a total of 409 Hb variants. The x-axis migration position showed excellent intra- and interassay precision. Comparison of Hb variants seen by both laboratories showed that 83% had a difference in migration position of 1 unit or less. Only three rare Hb variants showed a difference of more than 2 units. In summary, the CE migration position is a reproducible value and can be used as an aid in the identification of Hb variants.

Recognition of rare hemoglobin variants by hemoglobin A1c measurement procedures

BackgroundUnrecognized hemoglobinopathies can lead to measured hemoglobin A1c (Hb A1c) concentrations that are erroneous or misleading. We determined the effects of rare hemoglobin variants on capillary electrophoresis (CE) and HPLC methods for measurement of Hb A1c. MethodsWe prospectively investigated samples in which Hb A1c was measured by CE during a 14-month period. For samples in which the electropherograms suggested the presence of rare hemoglobinopathies, hemoglobin variants were identified by molecular analysis or by comparison with electropherograms of known variants. When sample volume permitted, Hb A1c was measured by 2 HPLC measurement procedures and by boronate affinity HPLC. ResultsHb A1c was measured by CE in 33,859 samples from 26,850 patients. 15 patients (0.06%) were identified as having rare hemoglobinopathies: Hbs A2 prime, Agenogi, Fannin-Lubbock I, G Philadelphia, G San Jose, J Baltimore, La Desirade, N Baltimore, Nouakchott, and Roanne. Among 6 of these samples tested by 2 ion-exchange HPLC methods, the rare Hb was detected by both HPLC methods in only one sample, and none were detected by boronate affinity HPLC. The mean of the Hb A1c results of 2 HPLC methods differed from the result of the CE method by 0.7–2.2% Hb A1c in samples with variant hemoglobins versus <0.2% Hb A1c in samples without variants. ConclusionMeasurement procedures differ in the ability to detect the presence of rare Hb variants and to quantify Hb A1c in patients who harbor such variants.

First Cases of Hb Agrinio Described in Patients from the Republic of Macedonia

Previous molecular analyses of α-thalassemia (α-thal) in the Republic of Macedonia have identified the following genetic defects: –α3.7 (rightward), –(α)20.5 and – –MED I deletions and Hb Icaria [α142, Term→Lys (α2), HBA2: c.427T>A] and polyadenylation signal (polyA) [AATAAA>AATGAA (α2), HBA2: c.*92A>G] point mutations. Here, we report two unrelated patients from the Romani population in the Republic of Macedonia, homozygotes for the α2-globin gene variant Hb Agrinio [α29(B10)Leu→Pro; HBA2: c.89T>C]. To date, Hb Agrinio has been described only in individuals of Greek, Cypriot and Spanish origin. Both of our patients had early presentation of the disease (3.5 years and 2 months, respectively) with frequent blood transfusions from early infancy. They have a severe intermediate phenotype of thalassemia (Hb H disease) with hemoglobin (Hb) levels of 7.8 and 7.7 g/dL, respectively. Although the HBA2: c.89T>C mutation results in an α+ allele, the severe phenotype of the homozygotes is due to the production of hyperunstable α chains that undergo post translational precipitation. This leads to a greater degree of red cell damage and hemolytic anemia. The detection of Hb Agrinio in two unrelated families of Romani ethnic origin, may suggest it is a founder mutation in this population living in the Republic of Macedonia. Considering the severity of the clinical presentation of the homozygotes or compound heterozygotes for this rare Hb variant, a targeted molecular screening for Hb Agrinio mutation carriers should be considered in all patients of Romani ethnic origin with manifested microcytosis.

Novel interactions of two α-Hb variants with SEA deletion α0-thalassemia: hematological and molecular analyses

ABSTRACTObjectives: To report the hematological and molecular features as well as diagnostic aspects of the hitherto un-described interactions of two rare α-globin chain variants with α0-thalassemia commonly found among Southeast Asian populations.Methods: The study was done on two adult Thai patients (P1 and P2) who had hypochromic microcytic anemia. Hb analysis was carried out using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). Mutations were identified by PCR and related techniques.Results: Hb analysis of P1 using HPLC showed a normal Hb pattern, but CE demonstrated an abnormal peak at zone 7. DNA sequencing identified a CCG-CTG mutation at codon 95 of the α2 globin gene corresponding to the Hb G-Georgia [α95(G2)Pro → Leu(α2)] previously undescribed in the Thai population. In contrast, Hb analysis of P2 demonstrated an abnormal peak not fully separated from Hb A on HPLC, but not on CE. DNA analysis identified the rarely described Hb Nakhon Ratchasima [α63(E12)Ala → Val(α2)] mutation. Routine DNA analysis detected the SEA deletion α0-thalassemia in trans to the Hb variants in both cases. Hematological parameters were compared with those of patients with compound heterozygote for other α-globin variants and α0-thalassemia previously documented.Conclusions: Identification of the patients confirmed that interaction of these rare Hb variants with α0-thalassemia does not lead to the Hb H disease. Differentiation of these two Hb variants from other clinically relevant hemoglobinopathies in a routine setting is, however, necessary. This can be accomplished using a combined Hb-HPLC and CE analysis followed by PCR-RFLP assays.

A Novel β-Globin Chain Hemoglobin Variant, Hb Allentown [β137(H15)Val→Trp (GTG>TGG) HBB: c.412_413delinsTG, p.Val138Trp], Associated with Low Oxygen Saturation, Intermittent Aplastic Crises and Splenomegaly

Hemoglobin (Hb) variants may be associated with low oxygen saturation and exacerbated episodes of anemia from common stressors such as viral infections. These attributes frequently cause increased clinical concern and unnecessary and expensive testing if not considered early in the evaluation of the patient. Some clinically significant Hb variants result in a normal Hb electrophoresis result, which can be method-dependent. Herein we describe a patient with low oxygen saturation and a history of hemolytic anemia who was subsequently found to carry a novel, unstable β-globin variant that we have named Hb Allentown [β137(H15)Val→Trp (GTG>TGG) HBB: c.412_413delinsTG, p.Val138Trp] for the place of identification of the variant. Hb Allentown is formed by a rare double nucleotide substitution within the same codon. Additionally, positive identification of rare Hb variants characterized by a single method is discouraged, as the Hb variant was misclassified as Hb S-South End or β6(A3)Glu→Val;β132(H10)Lys→Asn (HBB: c.[20A > T;399A > C]) by the initial laboratory.

Rare hemoglobin variants in Tunisian population.

During the last 30years, many studies concerning hemoglobinopathies were realized among Tunisians. More than twenty different thalassemic alleles were detected on the β-globin gene, and less are affecting the α-globin genes. Unusual hemoglobin (Hb) variants other than Hb S, Hb C, and Hb O-arab, which are the most frequent variants in Tunisia, were also detected. Eight Tunisian subjects were studied at phenotypic and molecular levels. Hematological indices and hemoglobin (Hb) pattern were performed by alkaline electrophoresis and isoelectric focusing (IEF),and the Hb fractions were quantitated by cation exchange HPLC. On genomic level, coding regions were amplified by polymerase chain reaction (PCR) followed by a sequencing of the purified PCR products using the dye terminator method. Seven uncommon Hb variants were detected and described for the first time among Tunisians. HbA2-Tunis [δ46(CD5), Gly → Glu, GGG → GAG] is the newly described δ-chain variant in our laboratory, and some other variants (Hb Constant Spring, G San Jose, and Hb J-Bangkok) are very uncommon in the Mediterranean region. We present here an updated review of the Hb variants detected among Tunisians. Twenty-one rare Hb variants were detected affecting the α1-, α2-, δ-, γ-, and β-globin genes, leading in some cases to a severe phenotype especially when the stability is completely altered. The ethnical history of Tunisia could explain this important variability of the observed rare Hb variants.

Fitness for Duty: Two Cases of Rare Hemoglobin Variants in U.S. Navy Recruits

There are many hemoglobin (Hb) variants that vary in prevalence as well as in clinical significance. Two young male military recruits were incidentally found to have two uncommon Hb variants. This led to an investigation of Hb Lepore-Boston and G-Waimanalo to determine if these U.S. Navy recruits were healthy enough to perform their designated duties. Literature search was conducted using PubMed/Medline. Keywords included "hemoglobinopathy," "hemoglobin variant," "Lepore-Boston," "G-Waimanalo." Results that included cases of Hb Lepore-Boston and G-Waimanalo literature were included. There are few reported cases of these Hb variants that have geographical patterns. It was discovered that Hb Lepore is a group of three variants, characterized by hybrid δβ chains, which expresses features of β-thalassemia trait in heterozygotes. Hb G-Waimanalo or α64(E13) Aspartic acid (Asp) → Asparagine (Asn) is a slow-moving α chain variant, which often results in a mild microcytic hypochromic anemia. Hb Lepore-Boston and G-Waimanalo are benign Hb variants that typically produce mild and asymptomatic anemia. With no clinical relevance in either of these rare Hb variants, the recruits were found qualified for both general duty and their specialty rates.

A Rare Hemoglobin Variant (Hb Iraq-Halabja) Causing Spuriously Low Hemoglobin A1c Values

Various laboratory and patient-related factors can affect the measurement of hemoglobin A1c (HbA1c). We herein present the case of a diabetic patient with spuriously low HbA1c values on ion-exchange high-performance liquid chromatography (HPLC). Further investigations revealed that the patient was heterozygous for a rare Hb variant, namely Hb Iraq-Halabja (β10 Ala→Val). This is the second report of this variant published in the literature. Clinicians should be aware of the limitations of HbA1c assays because inaccurate values may lead to the inappropriate management of diabetes. Unusual or discrepant HbA1c test results should prompt further investigations for potentially interfering factors, including rare Hb variants.

A comprehensive analysis of hemoglobin variants by high‐performance liquid chromatography (HPLC)

High-performance liquid chromatography (HPLC) is a method commonly used for the detection of hemoglobin (Hb) variants. In addition to providing precise quantitation of Hb A2 and Hb F, the reported retention time and peak shape of a high number of hemoglobin (Hb) variants are very helpful for presumptive identification. However, there is a scarcity of summarized data in the literature of the mobility of Hb variants on this method. A total of 383Hb variants were studied on the Bio-Rad Variant (™) Classic HPLC instrument. Hb variant identification used a number of methods, including confirmation by DNA sequencing in at least one case for all alpha and beta chain Hb variants. Retention time data and the number of occurrences of each Hb variant were obtained. This showed that rare Hb variants can have similar retention times to the five most common alpha or beta chain Hb variants. HPLC is a very powerful tool in the evaluation of Hb variants, particularly when combined with other methods. However, it should not be used as a stand-alone method for definitive identification of Hb variants.