Reliability of hemoglobin A2 value as measured by the Premier Resolution system for screening of β-thalassemia carriers

OBJECTIVES

Accurate quantification of hemoglobin (Hb) A2 is vital for diagnosing β-thalassemia carriers. This study aimed to assess the precision and diagnostic utility of HbA2 measurements using the new high-performance liquid chromatography (HPLC) method, Premier Resolution, in comparison to capillary electrophoresis (CE).

METHODS

We analyzed 418 samples, previously identified as A2A by CE, using Premier Resolution-HPLC. We compared the results, established correlations, and determined an optimal HbA2 cutoff value for β-thalassemia screening. Additionally, we prospectively evaluated the chosen cutoff value in 632 samples. Mutations in the β- and α-globin genes were identified using polymerase chain reaction (PCR) techniques and DNA sequencing.

RESULTS

HbA2 levels were consistently higher with Premier Resolution, yet there was a significant correlation with CE in all samples (bias, -0.33; r, 0.991), β-thalassemia (bias, -0.27; r, 0.927), and non-β-thalassemia carriers (bias, -0.36; r, 0.928). An HbA2 cutoff value of ≥4.0 % for β-thalassemia screening achieved 100 % sensitivity and 99.6 % specificity. Further validation yielded sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 97.3 , 99.8, 97.3, 99.8, and 99.7 %, respectively. We also identified a rare β-Hb variant, Hb La Desirade [HBB:c.389C>T], associated with β-thalassemia and co-inherited with a single α-globin gene.

CONCLUSIONS

The Premier Resolution HPLC is a reliable and accurate method for routine β-thalassemia carrier screening, aligning with existing CE methods.

Point-of-Care Diagnostic Test for Beta-Thalassemia

Hemoglobin (Hb) disorders are among the most common monogenic diseases affecting nearly 7% of the world population. Among various Hb disorders, approximately 1.5% of the world population carries β-thalassemia (β-Thal), affecting 40,000 newborns every year. Early screening and a timely diagnosis are essential for β-thalassemia patients for the prevention and management of later clinical complications. However, in Africa, Southern Europe, the Middle East, and Southeast Asia, where β-thalassemia is most prevalent, the diagnosis and screening for β-thalassemia are still challenging due to the cost and logistical burden of laboratory diagnostic tests. Here, we present Gazelle, which is a paper-based microchip electrophoresis platform that enables the first point-of-care diagnostic test for β-thalassemia. We evaluated the accuracy of Gazelle for the β-Thal screening across 372 subjects in the age range of 4-63 years at Apple Diagnostics lab in Mumbai, India. Additionally, 30 blood samples were prepared to mimic β-Thal intermediate and β-Thal major samples. Gazelle-detected levels of Hb A, Hb F, and Hb A2 demonstrated high levels of correlation with the results reported through laboratory gold standard high-performance liquid chromatography (HPLC), yielding a Pearson correlation coefficient = 0.99. This ability to obtain rapid and accurate results suggests that Gazelle may be suitable for the large-scale screening and diagnosis of β-Thal.

Research on the clinical factors of cardiac iron deposition in children with beta-thalassemia major

Magnetic resonance imaging (MRI) T2* is the gold standard for detecting iron deposition in cardiac tissue, but the technique has limitations and cannot be fully performed in paediatric thalassemia patients. The aim of this study was to analyse clinical data to identify other predictors of cardiac iron deposition. A retrospective analysis was performed on 370 children with β-TM. According to the cardiac MRI results, patients were allocated to a cardiac deposition group and noncardiac deposition group. Multivariate analysis revealed that genotype and corrected QT interval were associated with cardiac iron deposition, indicating that the-β0/β0 genotype conferred greater susceptibility to cardiac iron deposition. Receiver operating characteristic curve (ROC) analysis was performed, and the area under the curve (AUC) of genotype was 0.651. The AUC for the corrected QT interval was 0.711, at a cut-off value of 418.5 ms. ROC analysis of the combined genotype and corrected QT interval showed an AUC of 0.762 with 81.3% sensitivity and 64.7% specificity. Compared to patients with the β+/β+ and β0β+ genotypes, β0β0 children with β-TM were more likely to have cardiac iron deposition.  Conclusion: The genotype and QTc interval can be used to predict cardiac iron deposition in children with β-TM who are unable to undergo MRI T2 testing.

[Research progress on differential diagnosis of thalassemia trait and iron deficiency anemia by blood erythrocyte parameters]

Thalassemia trait is an autosomal recessive genetic disease, which is a hemolytic anemia caused by disturbance of erythrocyte hemoglobin production caused by gene mutation or deletion. Iron deficiency anemia is caused by a lack of iron in the body due to an imbalance between the demand and supply of iron. The laboratory manifestations of both are microcytic hypochromic anemia, but the treatment schemes are completely different, and it is difficult to distinguish them from the results of blood count. Erythrocyte parameters can be used to establish a formula or model to differentiate them, which can achieve the purpose of early screening, early diagnosis and early treatment,preventing the occurrence of severe anemia and providing a scientific basis for the thalassemia and iron deficiency anemia prevention. This article will review the research progress of using erythrocyte parameters to distinguish thalassemia trait with iron deficiency anemia.

Multi-criteria decision making to validate performance of RBC-based formulae to screen [Formula: see text]-thalassemia trait in heterogeneous haemoglobinopathies

BACKGROUND

India has the most significant number of children with thalassemia major worldwide, and about 10,000-15,000 children with the disease are born yearly. Scaling up e-health initiatives in rural areas using a cost-effective digital tool to provide healthcare access for all sections of people remains a challenge for government or semi-governmental institutions and agencies.

METHODS

We compared the performance of a recently developed formula SCS[Formula: see text] and its web application SUSOKA with 42 discrimination formulae presently available in the literature. 6,388 samples were collected from the Postgraduate Institute of Medical Education and Research, Chandigarh, in North-Western India. Performances of the formulae were evaluated by eight different measures: sensitivity, specificity, Youden's Index, AUC-ROC, accuracy, positive predictive value, negative predictive value, and false omission rate. Three multi-criteria decision-making (MCDM) methods, TOPSIS, COPRAS, and SECA, were implemented to rank formulae by ensuring a trade-off among the eight measures.

RESULTS

MCDM methods revealed that the Shine & Lal and SCS[Formula: see text] were the best-performing formulae. Further, a modification of the SCS[Formula: see text] formula was proposed, and validation was conducted with a data set containing 939 samples collected from Nil Ratan Sircar (NRS) Medical College and Hospital, Kolkata, in Eastern India. Our two-step approach emphasized the necessity of a molecular diagnosis for a lower number of the population. SCS[Formula: see text] along with the condition MCV[Formula: see text] 80 fl was recommended for a higher heterogeneous population set. It was found that SCS[Formula: see text] can classify all BTT samples with 100% sensitivity when MCV[Formula: see text] 80 fl.

CONCLUSIONS

We addressed the issue of how to integrate the higher-ranked formulae in mass screening to ensure higher performance through the MCDM approach. In real-life practice, it is sufficient for a screening algorithm to flag a particular sample as requiring or not requiring further specific confirmatory testing. Implementing discriminate functions in routine screening programs allows early identification; consequently, the cost will decrease, and the turnaround time in everyday workflows will also increase. Our proposed two-step procedure expedites such a process. It is concluded that for mass screening of BTT in a heterogeneous set of data, SCS[Formula: see text] and its web application SUSOKA can provide 100% sensitivity when MCV[Formula: see text] 80 fl.

Mutation spectrum of thalassemia among pre-pregnant adults in the Jiangsu Province by capillary electrophoresis-based multiplex PCR assay

BACKGROUND

Thalassemia is a common genetic disorder in southwestern China, and an increasing number of cases from eastern China have been recently reported. Here, we developed a rapid, convenient, and accurate assay to evaluate the mutation spectrum of thalassemia in eastern China.

METHODS

A carrier screening assay for 61 hotspot variants among HBA1/HBA2 and HBB (OMIM: 141800, 141850, and 141900) genes was developed by SNaPshot/high-throughput ligation-dependent probe amplification (HLPA) technology. We used this assay to detect the mutation spectrum of thalassemia in individuals from eastern China and compared with the data collected from literatures focused on southern and northern China for variant distribution.

RESULTS

Among 4276 tested individuals, 2.62% (112/4276) were α-thalassemia carriers, with 90 carrying one deletion or mutation and 22 carrying two deletions. 0.40% (17/4276) were β-thalassemia carriers, and the most common variant of β-thalassemia was c.126_129delCTTT (29.41%) followed by c.316-197C>T (23.53%). The genotype distribution in our study was similar to those from southern China populations.

CONCLUSION

The Chinese population from different regions presented comparable mutation spectrum of thalassemia, and the SNaPshot/HLPA technique may serve as a capable assay for a routine genetic test in clinical practice with its accurate, rapid, and inexpensive advantage.

Identification of a Novel Variant c.163delG in HBB Gene Resulting in a Beta Null Phenotype in a Proband with Thalassemia Intermedia

A 21-year-old patient presented with a previous medical history of pallor, mild icterus, increased fatigue, low hemoglobin, and abnormal hemoglobin variant analysis with more than 70 transfusions. He was referred for genetic analysis to identify the pathogenic variations in the β-globin gene. Sanger's sequencing of the proband and his family revealed the presence of a novel frame shift variant HBB:c.163delG in a compound heterozygous state with hemoglobin E (HbE) (HBB:c.79G > A) variant. The father and the sibling of the patient were found to be normal for the HBB gene. Mother was found to be heterozygous for HbE (HBB:c.79G > A) variant. In silico analysis by Mutalyzer predicted that c.163delG variant generated a premature stop codon after seven codons, leading to a truncated protein. FoldX protein stability analysis showed a positive ΔΔG value of 45.27 kcal/mol suggesting a decrease in protein stability. HBB:c.79G > A is a known variant coding for HbE variant, which results in the reduced synthesis of β-globin chain and shows mild thalassemia. Combined effect of HBB:c.163delG and HBB:c.79G > A variants in the proband might have led to the reduced synthesis of β-globin chains resulting in a thalassemia intermedia type of clinical manifestation.

Misdiagnosis of β-Thalassemia Major Due to Chinese Gγ+(Aγδβ)0-Thalassemia Combined with β0-Thalassemia

δβ-thalassemia is a rare type of thalassemia characterized by increased Hb F levels, including mainly Chinese Gγ(Aγδβ)0-thalassemia, Yunnanese Gγ(Aγδβ)0-thalassemia, Cantonese Gγ(Aγδβ)0-thalassemia in China. Due to the low rate of δβ-thalassemia carriers, there are few reports of δβ-thalassemia combined with β-thalassemia causing β-thalassemia major. Herein, we described the combination of Chinese Gγ(Aγδβ)0-thalassemia and β-thalassemia leading to β-thalassemia major in a Chinese patient. Hemoglobin analysis was performed by capillary electrophoresis (CE). Routine genetic analysis was carried out by gap-polymerase chain reaction (Gap-PCR) and PCR and reverse dot blot (PCR-RDB). Multiple ligation-dependent probe amplification (MLPA) was used to detect the large deletion, and Gap-PCR confirmed the deletion. A CE result showed an elevated Hb F level of 98.7% and 11.7% in the proband and her mother, but the proband was diagnosed with βCD17M/βCD17M using routine genetic analysis. However, her father was heterozygous for CD17 in β-globin, and her mother was detected as SEA heterozygous. The further analysis presented that the proband had actually missed the diagnosis of Chinese Gγ(Aγδβ)0-thalassemia by MLPA and PCR-RDB. Finally, the genotype of the proband was corrected from βCD17M/βCD17M to βCD17M/βGγ(Aγδβ)0. This is the first report of Chinese Gγ(Aγδβ)0-thalassemia combined with β-thalassemia resulting in β-thalassemia major in China. Screening for δβ-thalassemia by Hb analysis could be an effective method.

Premarital Screening is Pivotal in Reducing the Births of Babies Affected with Thalassemia Major in Iraq

Thalassemia major is one of the health problems in Iraq, especially in Kurdistan. Pre-marriage mandatory preventive screening program was established in Kurdistan in 2008, which allowed us to study the prevalence of different hemoglobinopathies among newly married young adults in this region. A total of 1154 subjects (577 couples) attending the Koya district, premarital Health center, were screened using red cell indices. Those who had mean corpuscular volume (MCV)<80 fl and mean corpuscular hemoglobin (MCH)<27 pg had high-performance liquid chromatography and iron studies. Out of 1154 individuals that were evaluated, 183 (11.9%) had low MCV and MCH. Of the former 183 subjects, 69 (5.97%) had β-thalassemia trait, 10 (0.86%) had δβ-thalassemia trait, and no other hemoglobinopathies were recorded in our study. There was second-degree consanguinity in 4.7% of all 577 couples. In two couples, both partners had β-thalassemia trait and both were consanguineous. Both couples decided to separate after counseling. Based on the current study, the role of the premarital screening program in decreasing the number of new thalassemia major cases among the Kurdish population is laudable. Therefore, mandatory premarital screening is advised in all parts of Iraq.

First Report of Filipino β0-Thalassemia/β-Thalassemia in a Chinese Family

A pregnant woman living in Fujian Province, southeastern China, presented due to a risk of having a baby with β-thalassemia major, during her second pregnancy, since she and her husband were suspected as β-thalassemia carriers and their affected daughter was a transfusion-dependent patient. Using the common α-thalassemia and β-thalassemia genotypes test, the pregnant woman was diagnosed as a β-thalassemia carrier with βIVS-2 - 654 (C→T)/βN genotype and her daughter had a homozygosity for IVS - 2 - 654 (C→T) mutation, however, no abnormalities were detected in her husband. SMRT identified a Filipino β0-deletion in her husband, and MLPA also revealed an unknown deletion in the HBB gene. Electrophoresis showed approximately 350 bp of the PCR product, and the β-Filipino genotype presented novel fracture fragments ranging from 5,112,884 to 5,231,358 bp, and lacked a 118,475 bp fragment relative to the wild-type sequence. The daughter was therefore diagnosed with the βIVS-2 - 654 (C→T)/βFilipino genotype. Prenatal diagnosis with umbilical cord blood at 27th week of gestation showed heteroztgosity for IVS - 2 - 654 (C→T) mutation in the fetus and continued pregnancy was recommended. In conclusion, we identified the Filipino β0-deletion in a Chinese family, from Fujian area, for the first time, during prenatal screening.

Clinical application of targeted long read sequencing in prenatal beta-thalassemia testing and genetic counseling

BACKGROUND

Beta thalassemia, related to HBB mutation and associated with elevated hemoglobin A2 (HbA2), is an important genetic hemoglobinopathy with high incidences of disease and carrier rates in Singapore. Carrier screening is essential to facilitate prenatal counseling and testing. However, when individuals with elevated HbA2 do not have an identifiable HBB disease-associated variant, there is ambiguity on risk to their offspring.

METHODS

We describe a case report of a proband with elevated HbA2, no identifiable HBB disease-associated variant, whose partner was a beta thalassemia carrier. Through clinical HBB gene sequencing, multiplex ligation-dependent probe amplification (MLPA) analysis, as well as targeted Nanopore long read sequencing of selected genes, we performed a complete analysis of HBB including the promoter region, 5'UTR and coding gene sequence, as well as evaluation for potential modifier variants and other rare structural variants.

RESULTS

This process identified that the proband was heterozygous for KLF1:c.544T>C (p.Phe182Leu), a potential functional polymorphism previously known to be associated with benign elevated HbA2 levels. The presence of disease variants in the HBB locus was excluded.

CONCLUSION

This finding provided clarity and enabled family planning for the proband and her family.

β0-Thalassemia Caused by a Novel Nonsense Mutation [c.199A > T]

We report two hemoglobinopathy cases involving a novel β-thalassemia (β-thal) nonsense mutation, HBB:c.199A > T. One patient had Hb S/β-thal, and a second unrelated patient had Hb D-Punjab/β-thal. The HBB:c.199A > T mutation introduces a premature termination codon at amino acid codon 66 (AAA→TAA) in exon 2, resulting in typical high Hb A2 β0-thal.

Unresolved laboratory issues of the heterozygous state of β-thalassemia: a literature review

Although considered a mild clinical condition, many laboratory issues of the carrier state of β-thalassemia remain unresolved. Accurate laboratory screening of β-thalassemia traits is crucial for preventing the birth of a β-thalassemia major child. Identification of carriers in the laboratory is affected by factors that influence red cell indices and HbA2 quantification. Silent mutations and co-inheriting genetic and non-genetic factors affect red cell indices which decreases the effectiveness of the conventional approach. Similarly, the type of β mutation, co-inheriting genetic and non-genetic factors, and technical aspects, including the analytical method used and variations in the HbA2 cut-off values, affect the HbA2 results, leading to further confusion. However, the combination of mean corpuscular volume, mean corpuscular hemoglobin, and hemoglobin analysis increases the diagnostic accuracy. Diagnostic problems arising from non-genetic factors can be eliminated by carefully screening the patient's clinical history. However, issues due to certain genetic factors, such as Krüppel-like factor 1 gene mutations and α triplication still remain unresolved. Each laboratory should determine the population-specific reference ranges and be wary of machine-related variations of HbA2 levels, the prevalence of silent mutations in the community.

Thurston syndrome with thalassaemia: a rare case devising a novel molecular and phenotypic variation

A male infant presented with progressive paleness of the body since 3 months of age. On examination, the child had pallor, microcephaly with dysmorphic facies (depressed nasal bridge, low set ears, retrognathia, high arched palate and tongue hamartoma). Postaxial polydactyly in bilateral hands and feet, broad great toes, with syndactyly of left fourth and fifth toes were present. The haemogram showed severe anaemia with a microcytic hypochromic picture. High-performance liquid chromatography (HPLC) was normal. However, the parents' HPLC was suggestive of beta thalassaemia trait. Whole-exome sequencing revealed Thurston syndrome with beta-thalassaemia in homozygous pattern with a novel mutation. It is a rare genetic syndrome exclusively found in the South Asian population. Due to the rarity, identification of this syndrome is often difficult and requires awareness among clinicians. However, it is important to diagnose the disorder accurately in order to provide appropriate genetic counselling and prognostication to the parents.

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

Objective

The capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC) methods were compared in terms of HbA2 measurement for the assessment of hemoglobinopathies.

Materials and Methods

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.

Results

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.

Conclusion

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.

Mutational spectrum of HBD gene in the Chinese population: Description of 36 mutations including 11 novel variants

INTRODUCTION

Mutations in the hemoglobin subunit delta (HBD) gene (MIM#142000) are associated with decreased levels of the Hemoglobin A2 (Hb A2 ) fraction. We aimed to examine the prevalence of HBD gene mutations and summarize their characteristics in the Chinese population.

METHODS

Individuals who exhibited Hb A2 levels below 1.8%, with or without Hb A2 variant peaks, were chosen for further investigation. Hemoglobin analysis was conducted using capillary electrophoresis. Common α and β-thalassemia in China were detected using gap-PCR and reverse dot blot hybridization. The presence of HBD gene mutations was confirmed by DNA sequencing.

RESULTS

A total of 188 patients were identified as carriers of the HBD gene mutation, with a prevalence of approximately 0.46%. We discovered 36 types of mutations, 30 of which resulted in δ-globin variants, while the remaining 6 resulted in δ-thalassemia. The most common mutation was HBD:c.-127 T > C, accounting for 87.2% of δ-thalassemia cases. In addition, we identified 11 novel HBD gene mutations and found 10 cases compounded with other common thalassemias.

CONCLUSION

We observed a high prevalence of HBD gene mutations in southern China. Our findings provide a genetic basis for screening for δ-thalassemia and enrich the spectrum of HBD gene mutations.

Whole exome sequencing and rare variant association study to identify genetic modifiers, KLF1 mutations, and a novel double mutation in Thai patients with hemoglobin E/beta-thalassemia

OBJECTIVES

Clinical manifestations of patients with Hemoglobin E/beta-thalassemia vary from mild to severe phenotypes despite exhibiting the same genotype. Studies have partially identified genetic modifiers. We aimed to study the association between rare variants in protein-coding regions and clinical severity in Thai patients.

METHODS

From April to November 2018, a case-control study was conducted based on clinical information and DNA samples collected from Thai patients with hemoglobin E/beta-thalassemia over the age of four years. Cases were patients with severe symptoms, while patients with mild symptoms acted as controls. Whole exome sequencing and rare variant association study were used to analyze the data.

RESULTS

All 338 unrelated patients were classified into 165 severe and 173 mild cases. Genotypes comprised 81.4% of hemoglobin E/beta-thalassemia, 2.7% of homozygous or compound heterozygous beta-thalassemia, and 0.3% of (δβ)⁰ thalassemia Hb E while 15.7% of samples were not classified as beta-thalassemia. A novel cis heterozygotes of IVS I-7 (A > T) and codon 26 (G > A) was identified. Six genes (COL4A3, DLK1, FAM186A, PZP, THPO, and TRIM51) showed the strongest associations with severity (observed p-values of <0.05; significance lost after correction for multiplicity). Among known modifiers, KLF1 variants were found in four mild patients and one severe patient.

CONCLUSION

No rare variants were identified as contributors to the clinical heterogeneity of hemoglobin E/beta-thalassemia. KLF1 mutations are potential genetic modifiers. Studies to identify genetic factors are still important and helpful for predicting severity and developing targeted therapy.

Detecting rare thalassemia in children with anemia using third-generation sequencing

BACKGROUND

In China, conventional genetic testing methods can only detect common thalassemia variants. Accurate detection of rare thalassemia is crucial for clinical diagnosis, especially for children that need long-term blood transfusion. This study aims to explore the application value of third-generation sequencing (TGS) in the diagnosis of rare thalassemia in children with anemia.

METHODS

We enrolled 20 children with anemia, excluding from iron deficiency anemia (IDA). TGS was employed to identify both known and novel thalassemia genotypes, while sanger sequencing was used to confirm the novel mutation detected.

RESULTS

Among the 20 samples, we identified 5 cases of rare thalassemia. These included β-4.9 (hg38,Chr11:5226187-5231089) at HBB gene, α-91(HBA2:c.*91delT), αCD30(HBA2:c.91-93delGAG), Chinese Gγ+(Aγδβ)0(NG_000007.3: g .48795-127698 del 78904) and delta - 77(T > C)(HBD:c.-127T>C). Notably, the -SEA/α-91α genotype associated with severe non-deletional hemoglobin H disease (HbH disease) has not been previously reported. Patients with genotypes β654/β-4.9 and -SEA/α-91α necessitate long-term blood transfusions, and those with the -SEA/αCD30α, Chinese Gγ+(Aγδβ)0 and delta thalassemia demonstrate mild anemia.

CONCLUSIONS

TGS demonstrates promising potential as a diagnostic tool for suspected cases of rare thalassemia in children, especially those suspected to have transfusion-dependent thalassemia (TDT).

A Rare Heterozygote with a Novel IVS-Ⅱ-786 (T>A) Mutation on β-Globin Gene in a Patient with Thalassemia

BACKGROUND

Thalassemia is an inherited hemolytic blood disease, whose pathogenesis is an imbalance in the expression of hemoglobin. We report a case of a rare β-globin gene intron mutation for thalassemia patient.

METHODS

The blood routine test was performed with an automatic blood cell analyzer. Hb analysis was conducted by hemoglobin (Hb) analyzer. The common β-thalassemia and α-thalassemia gene mutations were detected by Gap-PCR and fluorescence PCR melting curve, and the rare β-thalassemia gene mutations were detected by DNA sequencing.

RESULTS

A rare heterozygous mutation of β-globin gene IVS-II-786 (T>A) was found in this case. Blood routine analysis showed the following values: Hb 92 g/L, RBC 4.1 x 1012/L, MCV 74.10 fL, MCH 22.4 pg, MCHC 303 g/L, HCT 0.304 L/L, and RET-He 22.7 pg. Hemoglobin analysis showed values of HbA2 2.2% and HbF < 2% by automatic capillary electrophoresis. The results of gene analysis and DNA sequencing showed that the β-globin gene IVS-II-786 (T>A) mutation was heterozygous.

CONCLUSIONS

The heterozygote of β-globin gene IVS-II-786 (T>A) mutation was detected for the first time, and the clinical manifestation was moderate anemia. Hemoglobin analysis indicated that the level of HbA2 was decreased. This mutation is relatively rare and easy to misdiagnose in clinical practice. It will provide a new type of evidence and guidance for genetic counseling and clinical treatment of beta thalassemia.

Molecular characterisation of Hb Akron [β52 (D3) Asp→Val] combined with thalassaemia in a Chinese family

AIMS

Hb Akron (HBB:c.158A>T) is a rare β-chain variant and many characteristics about its clinical features still remain unclear. In this study, we aimed to explore the molecular and haematological characterisations of previously undescribed states for Hb Akron associated with different forms of thalassaemia.

METHODS

Haematology and genetic analysis were performed in 9 members from a Chinese Zhuang ethnic family.

RESULTS

Hb Akron in various combinations with β0-thalassaemia and α0-thalassaemia were identified and characterised. Simple heterozygote for Hb Akron is asymptomatic, while the compound heterozygotes of Hb Akron associated with the β0-thalassaemia mutation generates a more severe haematological phenotype than Hb Akron or β0-thalassaemia mutation seen in isolation. The specific peak of Hb Akron appears at Zone D (195-225 s) in the state of heterozygote and compound heterozygote on haemoglobin capillary electrophoresis device, and the reduction of Hb Akron level in heterozygotes is proportional to the degree of α-globin gene deficiency.

CONCLUSIONS

We have for the first time described the genetic and haematological characteristics of Hb Akron combined with different thalassaemia mutations, which will provide useful information for genetic counselling and prenatal diagnostic service of this mutation in a population with high prevalence of thalassaemia.

Transient presence of stomatocytes: A clue to the diagnosis of overhydrated hereditary stomatocytosis in a child with beta-thalassemia

BACKGROUND

Overhydrated hereditary stomatocytosis (OHSt) is a rare disorder characterized by abnormalities in erythrocytic volume homeostasis. Early and accurate diagnosis is essential for appropriate management and genetic counseling.

METHODS

We present the case of a child with beta-thalassemia and a history of multiple blood transfusions. Clinical presentation, laboratory findings, and genetic testing were reviewed. Peripheral blood smear examination and genetic analysis were performed.

RESULTS

The patient was admitted with severe anemia, and peripheral blood smear examination revealed the presence of up to 50% stomatocytes. Laboratory investigations showed abnormalities in red blood cell parameters, including decreased hemoglobin levels and increased mean corpuscular volume. Genetic testing identified a heterozygous mutation in the RHAG gene, confirming the diagnosis of OHSt. The presence of stomatocytes in the peripheral blood smear was transient, correlating with episodes of hemolysis and its control.