Detection of the common South-East Asian β<sup>0</sup>-thalassemia mutations in samples with borderline HbA<sub>2</sub> levels

Rungsee, Pitchaporn; Kongthai, Kanyakan; Pornprasert, Sakorn

doi:10.1515/cclm-2016-0470

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…Of 43 studies focusing on factors affecting HbA2 levels, 34.9% (n=15) reported the type of β-thalassemia mutation itself as one of the factors associated with reduced HbA2 level among β-thalassemia carriers. Four studies (26.7%) from Thailand, 36 , 53-55 three (20%) from Italy, 6 , 11 , 56 two (13.3%) from China, 33 , 34 two (13.3%) from India, 14 , 30 and one (6.7%) each from Iran, 38 Malaysia, 57 Saudi Arabia, 58 and Portugal 59 reported different types of β-thalassemia mutations resulting in borderline or normal HbA2 levels in β-thalassemia carriers.…”

Section: Resultsmentioning

confidence: 99%

“…Of 37 articles, the majority (48.6%; n=18) used 3.5% as the cut-off value, while 32.4% (n=12) of studies used 4.0% as the cut-off. Eighteen studies that used 3.5% as the cut-off include five from China, 18 , 21 , 32 , 34 , 70 five from Iran, 15 , 16 , 37 , 47 , 67 two from Thailand, 46 , 53 one each from India, 51 Bangladesh, 20 Saudi Arabia, 19 Portugal, 59 the UAE, 61 and the UK. 52 Similarly, 12 studies that used 4.0% as the cut-off include four from India, 7 , 17 , 27 , 48 four from Thailand, 35 , 49 , 51 , 55 and one each from Malaysia, 43 Bahrain, 42 Italy, 24 and the Netherlands.…”

Section: Resultsmentioning

confidence: 99%

“…If not, further genetic or molecular tests are necessary. 26 18.9 (7/37) -3.5-3.9 Jiang et al 34 17.7 (11/62) -Satthakarn et al 55 5.33 (16/300) -3.5-4.0 Rungsee et al 53 1.9 (3/158) Tested only for β 0 mutations Srivorakun et al 54 10.9 (22/202) -…”

Section: Discussionmentioning

confidence: 99%

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

Thilakarathne,

Jayaweera,

Premawardhena

2023

haematol

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Although considered a mild clinical condition, many laboratory issues of the carrier state of beta-thalassaemia remain unresolved. Accurate laboratory screening of beta-thalassaemia traits is crucial for preventing the birth of a beta-thalassaemia 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 beta mutation, co-inheriting genetic and non-genetic factors, and technical aspects, including the analytical method used and variations in the HbA2 cutoff values, affect the HbA2 results leading to further confusion. However, the combination of MCV, MCH and haemoglobin analysis increases the diagnostic accuracy. Diagnostic problems arising from non-genetic factors can be eliminated by carefully screening the patient’s clinical history. Still, issues due to certain genetic factors, such as Krüppel-like factor 1 gene mutations and alpha triplication remain unresolved. Each laboratory should determine the populationspecific reference ranges and be wary of machine-related variations of HbA2 levels, the prevalence of silent mutations in the community.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

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

Thilakarathne,

Jayaweera,

Premawardhena

2023

haematol

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Borderline HbA2 levels: Dilemma in diagnosis of beta-thalassemia carriers

Colaco

Nadkarni

2021

Mutation Research/Reviews in Mutation Research

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Significance of borderline HbA2 levels in β thalassemia carrier screening

Colaco

Colah

Nadkarni

2022

Sci Rep

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Increased HbA2 levels are the characteristic feature of β-thalassemia carriers. A subset of carriers however do not show HbA2 levels in the typical carrier range (≥ 4.0%) but show borderline HbA2 levels. As a result, these carriers escape diagnosis and carry the risk of having β-thalassemia major offspring. Borderline HbA2 values may occur as a consequence of mild β-thalassemia mutations, co-inherited β-thalassemia and α- or δ- thalassemia or iron deficiency anemia. However, there is insufficient knowledge regarding the cause of borderline HbA2 levels in specific populations. This study aimed to identify the determinants of borderline HbA2 levels (which we have considered as HbA2 3.0–3.9%) in 205 individuals. Primary screening involved detecting the presence of iron deficiency anemia followed by molecular analysis of α, β and δ globin genes. Remarkably, 168 of 205 individuals were positive for a defect. 87% (149/168) of positive individuals were heterozygous for β thalassemia with (59/149) or without (90/149) the presence of co-existing IDA, α or δ gene defects. Notably, 20 of 149 β thalassemia carriers showed HbA2 < 3.5% and MCV > 80fL. 7 of these 20 carriers were married to carriers of hemoglobinopathies. Our findings describe the genetic basis of borderline HbA2 levels and emphasize the necessity of a molecular diagnosis in these individuals in the routine clinical setting.

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Detection of the common South-East Asian β⁰-thalassemia mutations in samples with borderline HbA₂ levels

Cited by 4 publications

References 9 publications

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

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

Borderline HbA2 levels: Dilemma in diagnosis of beta-thalassemia carriers

Significance of borderline HbA2 levels in β thalassemia carrier screening

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Detection of the common South-East Asian β0-thalassemia mutations in samples with borderline HbA2 levels

Cited by 4 publications

References 9 publications

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

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

Borderline HbA2 levels: Dilemma in diagnosis of beta-thalassemia carriers

Significance of borderline HbA2 levels in β thalassemia carrier screening

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Product

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Detection of the common South-East Asian β⁰-thalassemia mutations in samples with borderline HbA₂ levels