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An assessment of three noncommercial DNA extraction methods from dried blood spots for beta-thalassaemia mutation identification

Karthipan SN, George E, Jameela S, Lim WF, Teh LK, Lee TY, et al.

Int J Lab Hematol, 2011 Oct;33(5):540-4.
PMID: 21884505 DOI: 10.1111/j.1751-553X.2011.01304.x

Dried blood spots (DBS) are currently the recommended sample collection method for newborn screening programmes in America. Early diagnosis of beta-thalassaemia screening is essential as it provides an added advantage especially in sickle cell disease. Beta-thalassaemia frequency is high in many poor countries, and the cost of using commercial DNA extraction kits can be prohibitive. Our study assessed three methods that use minimal reagents and materials to extract DNA from DBS for beta-thalassaemia identification.

Matched MeSH terms: beta-Thalassemia/diagnosis*; beta-Thalassemia/genetics*
Fulltext Non-invasive prenatal diagnosis using fetal DNA in maternal plasma: a preliminary study for identification of paternally-inherited alleles using single nucleotide polymorphisms

Chen JJ, Tan JA, Chua KH, Tan PC, George E

BMJ Open, 2015 Jul 22;5(7):e007648.
PMID: 26201722 DOI: 10.1136/bmjopen-2015-007648

OBJECTIVES: Single nucleotide polymorphism (SNP) with a mutation can be used to identify the presence of the paternally-inherited wild-type or mutant allele as result of the inheritance of either allele in the fetus and allows the prediction of the fetal genotype. This study aims to identify paternal SNPs located at the flanking regions upstream or downstream from the β-globin gene mutations at CD41/42 (HBB:c.127_130delCTTT), IVS1-5 (HBB:c.92+5G>C) and IVS2-654 (HBB:c.316-197C>T) using free-circulating fetal DNA.
SETTING: Haematology Lab, Department of Biomedical Science, University of Malaya.
PARTICIPANTS: Eight couples characterised as β-thalassaemia carriers where both partners posed the same β-globin gene mutations at CD41/42, IVS1-5 and IVS2-654, were recruited in this study.
OUTCOME MEASURES: Genotyping was performed by allele specific-PCR and the locations of SNPs were identified after sequencing alignment.
RESULTS: Genotype analysis revealed that at least one paternal SNP was present for each of the couples. Amplification on free-circulating DNA revealed that the paternal mutant allele of SNP was present in three fcDNA. Thus, the fetuses may be β-thalassaemia carriers or β-thalassaemia major. Paternal wild-type alleles of SNP were present in the remaining five fcDNA samples, thus indicating that the fetal genotypes would not be homozygous mutants.
CONCLUSIONS: This preliminary research demonstrates that paternal allele of SNP can be used as a non-invasive prenatal diagnosis approach for at-risk couples to determine the β-thalassaemia status of the fetus.

Matched MeSH terms: beta-Thalassemia/diagnosis*; beta-Thalassemia/genetics
Fulltext Spectrum of beta-thalassaemia mutations in transfusion dependent thalassaemia patients: practical implications in prenatal diagnosis

George E, George R, Ariffin WA, Mokhtar AB, Azman ZA, Sivagengei K

Med J Malaysia, 1993 Sep;48(3):325-9.
PMID: 8183146

The study concerned the identification of the beta-thalassaemia mutations that were present in 24 patients with beta-thalassaemia major who were transfusion dependent. The application of a modified polymerase chain reaction, the amplification refractory system (ARMS) was found to be an effective and rapid method for the identification of the beta-thalassaemia mutations. Six different mutations were detected. Seventy five percent of the patients were Chinese-Malaysians and showed the commonly occurring anomalies: 1. frameshift codon 41 and 42 (-TCTT); 2. the C to T substitution at position 654 of intron 2 (IVS-2); 3. the mutation at position -28(A to G); and the nonsense mutation A to T at codon 17. In the Malays, the common mutations seen were: 1. the G to C mutation at position 5 of IVS-1; 2. the G to T mutation at position 1 of intron 1 (IVS-1); and the A to T at codon 17. The delineation of the specific mutations present will enable effective prenatal diagnosis for beta-thalassaemia to be instituted.

Matched MeSH terms: beta-Thalassemia/diagnosis; beta-Thalassemia/genetics*
Preimplantation genetic diagnosis for beta-thalassemia using single-cell DNA analysis for codons 17 and 26 of beta-globin gene

Nasri NW, Jamal AR, Abdullah NC, Razi ZR, Mokhtar NM

Arch Med Res, 2009 Jan;40(1):1-9.
PMID: 19064120 DOI: 10.1016/j.arcmed.2008.10.008

Preimplantation genetic diagnosis (PGD) of monogenic autosomal hereditary disorders following assisted conception usually involves the removal of one or two blastomeres from preimplantation embryos. However, the amount of DNA from a single blastomere is insufficient to amplify the region of interest. Hence, the whole genome amplification (WGA) method is performed prior to amplifying the genes of interest before analysis of DNA material through polymerase chain reaction (PCR).

Matched MeSH terms: beta-Thalassemia/diagnosis*; beta-Thalassemia/genetics
Fulltext HbE/β-Thalassemia and Oxidative Stress: The Key to Pathophysiological Mechanisms and Novel Therapeutics

Hirsch RE, Sibmooh N, Fucharoen S, Friedman JM

Antioxid Redox Signal, 2017 05 10;26(14):794-813.
PMID: 27650096 DOI: 10.1089/ars.2016.6806

SIGNIFICANCE: Oxidative stress and generation of free radicals are fundamental in initiating pathophysiological mechanisms leading to an inflammatory cascade resulting in high rates of morbidity and death from many inherited point mutation-derived hemoglobinopathies. Hemoglobin (Hb)E is the most common point mutation worldwide. The βE-globin gene is found in greatest frequency in Southeast Asia, including Thailand, Malaysia, Indonesia, Vietnam, Cambodia, and Laos. With the wave of worldwide migration, it is entering the gene pool of diverse populations with greater consequences than expected.
CRITICAL ISSUES: While HbE by itself presents as a mild anemia and a single gene for β-thalassemia is not serious, it remains unexplained why HbE/β-thalassemia (HbE/β-thal) is a grave disease with high morbidity and mortality. Patients often exhibit defective physical development, severe chronic anemia, and often die of cardiovascular disease and severe infections. Recent Advances: This article presents an overview of HbE/β-thal disease with an emphasis on new findings pointing to pathophysiological mechanisms derived from and initiated by the dysfunctional property of HbE as a reduced nitrite reductase concomitant with excess α-chains exacerbating unstable HbE, leading to a combination of nitric oxide imbalance, oxidative stress, and proinflammatory events.
FUTURE DIRECTIONS: Additionally, we present new therapeutic strategies that are based on the emerging molecular-level understanding of the pathophysiology of this and other hemoglobinopathies. These strategies are designed to short-circuit the inflammatory cascade leading to devastating chronic morbidity and fatal consequences. Antioxid. Redox Signal. 26, 794-813.

Matched MeSH terms: beta-Thalassemia/genetics; beta-Thalassemia/metabolism*
Microcytic to hypochromic ratio as a discriminant index of thalassaemia trait in subjects with hypochromic anaemia

Wee SY, Muhamed Said SS, Raja Sabudin RZA, Alauddin H, Ithnin A

Malays J Pathol, 2020 Aug;42(2):195-201.
PMID: 32860371

INTRODUCTION: Differentiating between thalassaemia and iron deficiency anaemia (IDA) in hypochromic anaemia is a challenge to pathologists as it influences the choice of subsequent specialized confirmatory tests. In this study, we aimed to evaluate the performance of microcytic to hypochromic ratio (MicroR/ Hypo-He, M/H ratio) as a discriminant index in hypochromic anaemia.
MATERIALS AND METHODS: A retrospective study was carried out on 318 subjects with hypochromic anaemia, which comprised 162 IDA and 156 thalassaemia trait subjects with α-thalassemia, β-thalassemia and HbE trait. Optimal cut-off value, sensitivity and specificity of M/H ratio for thalassaemia trait discrimination was determined using Receiver Operating Characteristic (ROC) analysis.
RESULTS: Subjects with thalassaemia trait showed higher MicroR compared to IDA ( p< 0.001) while subjects with IDA demonstrated higher Hypo-He than thalassaemia trait (p < 0.001). M/H ratio was significantly higher in thalassaemia trait compared to IDA, with medians of 3.77 (interquartile range: 2.57 - 6.52) and 1.73 (interquartile range: 1.27 - 2.38), respectively (p < 0.001). M/H ratio ≥ 2.25 was the optimal cut-off value for discriminating thalassaemia trait from IDA in hypochromic anaemia, with the area under ROC curve (AUC) of 0.83, sensitivity of 80.8% and specificity of 71.6%.
CONCLUSIONS: M/H ratio is a useful discriminant index to distinguish thalassaemia trait from IDA in hypochromic anaemia prior to diagnostic analysis for thalassaemia confirmation. High M/H ratio is suggestive of thalassaemia trait than of IDA. However, more studies are required to establish the role of M/H ratio as a screening tool for thalassaemia discrimination in hypochromic anaemia.

Matched MeSH terms: beta-Thalassemia/diagnosis; beta-Thalassemia/pathology
Fatal Campylobacter jejuni infection in a patient splenectomised for thalassaemia

Jackson N, Zaki M, Rahman AR, Nazim M, Win MN, Osman S

J Clin Pathol, 1997 May;50(5):436-7.
PMID: 9215130

A 35 year old man with a fatal Campylobacter jejuni infection is described. He had HbE/beta zero thalassaemia and had undergone splenectomy nine months previously for hypersplenism; he also had chronic hepatitis C infection. He presented with high grade fever but no gastrointestinal symptoms and rapidly progressed to septicaemic shock and hepatic encephalopathy despite treatment with penicillin, gentamicin, and, later, chloramphenicol and ceftazidime. Only one case of Campylobacter jejuni septicaemia occurring post-splenectomy has been reported previously, also in an iron overloaded thalassaemia patient. Unusual Gram negative bacilli must be covered by the chosen antibiotic regimen when splenectomised thalassaemic patients present with high grade fever.

Matched MeSH terms: beta-Thalassemia/complications; beta-Thalassemia/surgery*
Molecular Characterisation of α- and β-Thalassaemia among Indigenous Senoi Orang Asli Communities in Peninsular Malaysia

Koh DXR, Raja Sabudin RZA, Mohd Yusoff M, Hussin NH, Ahmad R, Othman A, et al.

Ann. Hum. Genet., 2017 Sep;81(5):205-212.
PMID: 28620953 DOI: 10.1111/ahg.12201

Thalassaemia is a public health problem in Malaysia, with each ethnic group having their own common mutations. However, there is a lack on data on the prevalence and common mutations among the indigenous people. This cross-sectional study was performed to determine the common mutations of α- and β-thalassaemia among the subethnic groups of Senoi, the largest Orang Asli group in Peninsular Malaysia. Blood samples collected from six Senoi subethnic groups were analysed for full blood count and haemoglobin analysis (HbAn). Samples with abnormal findings were then screened for α- and β-globin gene mutations. Out of the 752 samples collected, 255 showed abnormal HbAn results, and 122 cases showing abnormal red cell indices with normal HbAn findings were subjected to molecular screening. DNA analysis revealed a mixture of α- and β-globin gene mutations with 25 concomitant cases. The types of gene abnormalities detected for α-thalassaemia were termination codon (T>C) Hb CS (αCS α), Cd59 (G>A) haemoglobin Adana (Hb Adana) (αCd59 α), initiation codon (ATG>A-G) (αIniCd α), two-gene deletion (-SEA ), and single-gene 3.7-kb deletion (-α3.7 ). For β-thalassaemia, there were Cd26 (G>A) Hb E (βE ), Cd19 (A>G) Haemoglobin Malay (Hb Malay) (βCd19 ), and IVS 1-5 (G>C) (βIVS 1-5 ).

Matched MeSH terms: beta-Thalassemia/genetics*; beta-Thalassemia/epidemiology
Fulltext Molecular characterization of α- and β-thalassaemia among Malay patients

Yatim NF, Rahim MA, Menon K, Al-Hassan FM, Ahmad R, Manocha AB, et al.

Int J Mol Sci, 2014 May 19;15(5):8835-45.
PMID: 24857915 DOI: 10.3390/ijms15058835

Both α- and β-thalassaemia syndromes are public health problems in the multi-ethnic population of Malaysia. To molecularly characterise the α- and β-thalassaemia deletions and mutations among Malays from Penang, Gap-PCR and multiplexed amplification refractory mutation systems were used to study 13 α-thalassaemia determinants and 20 β-thalassaemia mutations in 28 and 40 unrelated Malays, respectively. Four α-thalassaemia deletions and mutations were demonstrated. --SEA deletion and αCSα accounted for more than 70% of the α-thalassaemia alleles. Out of the 20 β-thalassaemia alleles studied, nine different β-thalassaemia mutations were identified of which βE accounted for more than 40%. We concluded that the highest prevalence of (α- and β-thalassaemia alleles in the Malays from Penang are --SEA deletion and βE mutation, respectively.

Matched MeSH terms: beta-Thalassemia/genetics*; beta-Thalassemia/pathology
Fulltext The use of the amplification refractory mutation system (arms) in the detection of rare beta-thalassemia mutations in the Malays and Chinese in Malaysia

Chan YF, Tan KL, Wong YC, Wee YC, Yap SF, Tan JAMA

Southeast Asian J Trop Med Public Health, 2001 Dec;32(4):872-9.
PMID: 12041567

Molecular characterization and prenatal diagnosis for beta-thalassemia can be carried out using the Amplification Refractory Mutation System (ARMS). The ARMS is a rapid and direct molecular technique in which beta-thalassemia mutations are visualized immediately after DNA amplification by gel electrophoresis. In the University of Malaya Medical Center, molecular characterization and prenatal diagnosis for beta-thalassemia is carried out using ARMS for about 96% of the Chinese and 84.6% of the Malay patients. The remaining 4% and 15.4% of the uncharacterized mutations in the Chinese and Malay patients respectively are detected using DNA sequencing. DNA sequencing is an accurate technique but it is more time-consuming and expensive compared with the ARMS. The ARMS for the rare Chinese beta-mutations at position -29 (A-->G) and the ATG-->AGG base substitution at the initiator codon for translation in the beta-gene was developed. In the Malays, ARMS was optimized for the beta-mutations at codon 8/9 (+G), Cap (+1) (A-->C) and the AATAAA-->AATAGA base substitution in the polyadenylation region of the beta-gene. The ARMS protocols were developed by optimization of the parameters for DNA amplification to ensure sensitivity, specificity and reproducibility. ARMS primers (sequences and concentration), magnesium chloride concentration, Taq DNA polymerase and PCR cycling parameters were optimized for the specific amplification of each rare beta-thalassemia mutation. The newly-developed ARMS for the 5 rare beta-thalassemia mutations in the Chinese and Malays in Malaysia will allow for more rapid and cost-effective molecular characterization and prenatal diagnosis for beta-thalassemia in Malaysia.

Matched MeSH terms: beta-Thalassemia/diagnosis; beta-Thalassemia/genetics*
Fulltext The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan

Abdullah WA, Jamaluddin NB, Kham SK, Tan JA

Southeast Asian J Trop Med Public Health, 1996 Mar;27(1):164-8.
PMID: 9031421

The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan (Northeast Malaysia) was studied. Allele specific priming was used to determine the mutations in beta-carriers at -28, Codon 17, IVSI #1, IVSI #5, Codon 41-42 and IVSII #654 along the beta-globin gene. The most common structural hemoglobin variant in Southeast Asia, Hb E, was detected by DNA amplification with restriction enzyme (Mnl1) analysis. Direct genomic sequencing was carried out to detect the beta-mutations uncharacterized by allele-specific priming. The most prevalent beta-mutations in Singaporean Malays were IVSI #5 (45.83%) followed by Hb E (20.83%), codon 15 (12.5%) and IVSI #1 and IVSII #654 at 4.17% each. In contrast, the distribution of the beta-mutations in Kelantan Malays differed, with Hb E as the most common mutation (39.29%) followed by IVSI #5 (17.86%), codon 41-42 (14.29%), codon 19 (10.71%) and codon 17 (3.57%). The beta-mutations in Kelantan Malays follow closely the distribution of beta-mutations in Thais and Malays of Southern Thailand and Malays of West Malaysia. The AAC-->AGC base substitution in codon 19 has been detected only in these populations. The spectrum of beta-mutations in the Singaporean Malays is more similar to those reported in Indonesia with the beta-mutation at codon 15 (TGG-->TAG) present in both populations. The characterization of beta-mutations in Singaporean and Kelantan Malays will facilitate the establishment of effective prenatal diagnosis programs for beta-thalassemia major in this ethnic group.

Matched MeSH terms: beta-Thalassemia/ethnology; beta-Thalassemia/genetics*
Fulltext Growth velocity in transfusion dependent prepubertal thalassemia patients: results from a thalassemia center in Malaysia

Hamidah A, Arini MI, Zarina AL, Zulkifli SZ, Jamal R

Southeast Asian J Trop Med Public Health, 2008 Sep;39(5):900-5.
PMID: 19058587

Growth impairment is commonly seen in children with thalassemia despite regular blood transfusions and desferrioxamine treatments. We investigated the growth velocity of 26 prepubertal patients with beta-thalassemia or HbE-beta thalassemia who were transfusion dependent aged between 2 and 13 years. The prevalence of impaired growth velocity (ie, growth velocity less than the third percentile) amongst the transfusion dependent prepubertal thalassemics was 57.7% compared to 19.2% in the control group. The mean height velocity of the thalassemics was 11.1% less than controls but this difference was not statistically significant (4.23cm/year vs 4.76cm/year, p = 0.08). The mean serum ferritin level of the thalassemics with a height < 3rd percentile was higher compared to those with a height > 3rd percentile (4,567.0 vs 2,271.0, p = 0.01). Our study showed that there was a high prevalence of impaired growth velocity amongst our transfusion dependent prepubertal thalassemics. This highlights the problem of inadequate chelation therapy, and compliance with chelation therapy amongst our patients. This study emphasizes the importance of monitoring growth parameters and optimal iron chelation therapy in these patients.

Matched MeSH terms: beta-Thalassemia/physiopathology; beta-Thalassemia/therapy*
The clinical severity of beta-thalassemia mutations in West Malaysia

George E

Southeast Asian J Trop Med Public Health, 1995;26 Suppl 1:225-8.
PMID: 8629111

Beta-thalassemia in West Malaysia is caused by 14 molecular defects with differing clinical severity. In Chinese patients from West Malaysia, the main beta-thalassemia mutations seen were (a) a 4 base pair-TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)]; (b) a C to T substitution at the second intervening sequence (IVS2-654); (c) an A to G substitution in the TATA box [-28 (A to G)], and (d) an A to T substitution in codon 17[17 A to T]. In the Malays, the main mutations seen were (a) a G to C in nucleotide 5 at the intervening sequence I [IVS1-5 (G to C)]; (b) G to T substitution in nucleotide I at the intervening sequence I [IVS1-1 (G to T)]; (c) a A to T substitution in codon 17 (17 A to T); (d) removal of C from codon 35 [codon 35 (-C)], and (e) a 4 base pairs-TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)]. A scoring system (Tha1 CS) has been formulated to predict clinical severity. It is the type of beta-thalassemia mutation present that decides on the clinical phenotype. The most severe beta-thalassemia mutation is assigned a score of 4. A score of 8 indicates severe thalassemia.

Matched MeSH terms: beta-Thalassemia/genetics*; beta-Thalassemia/physiopathology*
Genetic problems and genetic services in Malaysia: a country report

Hassan K

Southeast Asian J Trop Med Public Health, 1995;26 Suppl 1:11-5.
PMID: 8629087
Matched MeSH terms: beta-Thalassemia/genetics; beta-Thalassemia/epidemiology*
Hydroxyurea for reducing blood transfusion in non-transfusion dependent beta thalassaemias

Foong WC, Ho JJ, Loh CK, Viprakasit V

Cochrane Database Syst Rev, 2016 Oct 18;10(10):CD011579.
PMID: 27755646

BACKGROUND: Non-transfusion dependent beta thalassaemia is a subset of inherited haemoglobin disorders characterised by reduced production of the beta globin chain of the haemoglobin molecule leading to anaemia of varying severity. Although blood transfusion is not a necessity for survival, it is required when episodes of chronic anaemia occur. This chronic anaemia can impair growth and affect quality of life. People with non-transfusion dependent beta thalassaemia suffer from iron overload due to their body's increased capability of absorbing iron from food sources. Iron overload becomes more pronounced in those requiring blood transfusion. People with a higher foetal haemoglobin level have been found to require fewer blood transfusions. Hydroxyurea has been used to increase foetal haemoglobin level; however, its efficacy in reducing transfusion, chronic anaemia complications and its safety need to be established.
OBJECTIVES: To assess the effectiveness, safety and appropriate dose regimen of hydroxyurea in people with non-transfusion dependent beta thalassaemia (haemoglobin E combined with beta thalassaemia and beta thalassaemia intermedia).
SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of relevant journals. We also searched ongoing trials registries and the reference lists of relevant articles and reviews.Date of last search: 30 April 2016.
SELECTION CRITERIA: Randomised or quasi-randomised controlled trials of hydroxyurea in people with non-transfusion dependent beta thalassaemia comparing hydroxyurea with placebo or standard treatment or comparing different doses of hydroxyurea.
DATA COLLECTION AND ANALYSIS: Two authors independently applied the inclusion criteria in order to select trials for inclusion. Both authors assessed the risk of bias of trials and extracted the data. A third author verified these assessments.
MAIN RESULTS: No trials comparing hydroxyurea with placebo or standard care were found. However, we included one randomised controlled trial (n = 61) comparing 20 mg/kg/day with 10 mg/kg/day of hydroxyurea for 24 weeks.Both haemoglobin and foetal haemoglobin levels were lower at 24 weeks in the 20 mg group compared with the 10 mg group, mean difference -2.39 (95% confidence interval - 2.8 to -1.98) and mean difference -1.5 (95% confidence interval -1.83 to -1.17), respectively. Major adverse effects were significantly more common in the 20 mg group, for neutropenia risk ratio 9.93 (95% confidence interval 1.34 to 73.97) and for thrombocytopenia risk ratio 3.68 (95% confidence interval 1.13 to 12.07). No difference was reported for minor adverse effects (gastrointestinal disturbances and raised liver enzymes). The effect of hydroxyurea on transfusion frequency was not reported.The overall quality for the outcomes reported was graded as very low mainly because the outcomes were derived from only one small study with an unclear method of allocation concealment.
AUTHORS' CONCLUSIONS: There is no evidence from randomised controlled trials to show whether hydroxyurea has any effect compared with controls on the need for blood transfusion. Administration of 10 mg/kg/day compared to 20 mg/kg/day of hydroxyurea resulted in higher haemoglobin levels and seems safer with fewer adverse effects. It has not been reported whether hydroxyurea is capable of reducing the need for blood transfusion. Large well-designed randomised controlled trials with sufficient duration of follow up are recommended.

Matched MeSH terms: beta-Thalassemia/blood; beta-Thalassemia/drug therapy*
Beta-thalassaemia mutations in west Malaysia: a new thalassaemia clinical score system

George E

Ann Acad Med Singap, 1994 Jan;23(1):89-93.
PMID: 7514384

The clinical severity of the mutations causing beta-thalassaemia in West Malaysia is presented. Thalassaemia clinical scores (Thal CS), a scoring system, has been formulated to predict clinical severity. It is the type of beta-thalassaemia mutation present that decides on the clinical phenotype. The most severe beta-thalassaemia mutation is assigned a score of 4. A score of 8 indicates a severe thalassaemia phenotype. Alpha-thalassaemia, increased synthesis of Hb F, and glucose-6-phosphate deficiency may ameliorate the clinical condition at phenotype level, and the co-inheritance of hereditary ovalocytosis aggravates it.

Matched MeSH terms: beta-Thalassemia/diagnosis*; beta-Thalassemia/genetics*
Genotype-Phenotype Correlation of β-Thalassemia in Malaysian Population: Toward Effective Genetic Counseling

Abdullah UYH, Ibrahim HM, Mahmud NB, Salleh MZ, Teh LK, Noorizhab MNFB, et al.

Hemoglobin, 2020 May;44(3):184-189.
PMID: 32586164 DOI: 10.1080/03630269.2020.1781652

Effective prevention of β-thalassemia (β-thal) requires strategies to detect at-risk couples. This is the first study attempting to assess the prevalence of silent β-thal carriers in the Malaysian population. Hematological and clinical parameters were evaluated in healthy blood donors and patients with β-thal trait, Hb E (HBB: c.79G>A)/β-thal and β-thal major (β-TM). β-Globin gene sequencing was carried out for 52 healthy blood donors, 48 patients with Hb E/β-thal, 34 patients with β-TM and 38 patients with β-thal trait. The prevalence of silent β-thal carrier phenotypes found in 25.0% of healthy Malaysian blood donors indicates the need for clinician's awareness of this type in evaluating β-thal in Malaysia. Patients with β-TM present at a significantly younger age at initial diagnosis and require more blood transfusions compared to those with Hb E/β-thal. The time at which genomic DNA was extracted after blood collection, particularly from patients with β-TM and Hb E/β-thal, was found to be an important determinant of the quality of the results of the β-globin sequencing. Public education and communication campaigns are recommended as apparently healthy individuals have few or no symptoms and normal or borderline hematological parameters. β-Globin gene mutation characterization and screening for silent β-thal carriers in regions prevalent with β-thal are recommended to develop more effective genetic counseling and management of β-thal.

Matched MeSH terms: beta-Thalassemia/blood; beta-Thalassemia/diagnosis; beta-Thalassemia/genetics*; beta-Thalassemia/epidemiology*
Fulltext Thalassemia major is a major risk factor for pediatric melioidosis in Kota Kinabalu, Sabah, Malaysia

Fong SM, Wong KJ, Fukushima M, Yeo TW

Clin Infect Dis, 2015 Jun 15;60(12):1802-7.
PMID: 25767257 DOI: 10.1093/cid/civ189

Melioidosis is an important cause of community-acquired infection in Southeast Asia and northern Australia. Studies from endemic countries have demonstrated differences in the epidemiology and clinical features among children diagnosed with melioidosis. This suggests that local data are needed to determine the risk factors and outcome in specific areas.

Matched MeSH terms: beta-Thalassemia/complications*; beta-Thalassemia/epidemiology*
Bone-related complications of transfusion-dependent beta thalassemia among children and adolescents

Mirhosseini NZ, Shahar S, Ghayour-Mobarhan M, Banihashem A, Kamaruddin NA, Hatef MR, et al.

J. Bone Miner. Metab., 2013 Jul;31(4):468-76.
PMID: 23475127 DOI: 10.1007/s00774-013-0433-1

Thalassemia and the blood transfusion complications associated with it predispose children to poor bone health. This study was conducted to determine the prevalence of bone-related abnormalities and identify the bone health predictors within this population. One hundred and forty transfusion-dependent beta thalassemic subjects 8-18 years old in Mashhad, Iran, participated in this cross-sectional study. Anthropometric measures, dietary intake, bone-related biomarkers and bone densitometry, were assessed. The incidence of underweight and short stature was 33.6 and 41.4 %, respectively, which were indicators of malnutrition among thalassemic subjects in this study. Low bone density was detected in the lumbar spine and femoral region in 82 and 52 % of subjects, respectively. Hypocalcemia and hypophosphatemia were seen in 22 and 18.2 %, whilst vitamin D deficiency was present in more than 85 % of thalassemic children and adolescents. The relationships between weight, height and other anthropometric indices, serum calcium and bone markers, intake of macronutrients, zinc and vitamin E with bone mineral density (BMD) and bone mineral content (BMC) in the lumbar spine and femoral area were positively related, indicating that better nutritional status were associated with higher BMD and BMC values. Puberty, gender and serum osteocalcin were negative predictors for BMD and BMC values, whereas age, weight and height were the positive predictors. High incidence of low bone density and deficit in other aspects of bone health among thalassemia patients makes routine bone health assessment necessary for this vulnerable group. Considering influencing factors, dietary counseling and preventive supplementation therapy for this high risk group of children and adolescents may be necessary, although this should be assessed by intervention studies.

Matched MeSH terms: beta-Thalassemia/physiopathology; beta-Thalassemia/therapy*
Fulltext Specific and straightforward molecular investigation of β-thalassemia mutations in the Malaysian Malays and Chinese using direct TaqMan genotyping assays

Kho SL, Chua KH, George E, Tan JA

Genet. Mol. Res., 2013;12(3):2409-15.
PMID: 23479149 DOI: 10.4238/2013.February.28.4

Beta-thalassemia is a life-threatening inherited blood disorder. Rapid characterization of β-globin gene mutations is necessary because of the high frequency of Malaysian β-thalassemia carriers. A combination real-time polymerase chain reaction genotyping assay using TaqMan probes was developed to confirm β-globin gene mutations. In this study, primers and probes were designed to specifically identify 8 common β-thalassemia mutations in the Malaysian Malay and Chinese ethnic groups using the Primer Express software. "Blind tests" using DNA samples from healthy individuals and β-thalassemia patients with different genotypes were performed to determine the specificity and sensitivity of this newly designed assay. Our results showed 100% sensitivity and specificity for this novel assay. In conclusion, the TaqMan genotyping assay is a straightforward assay that allows detection of β-globin gene mutations in less than 40 min. The simplicity and reproducibility of the TaqMan genotyping assay permit its use in laboratories as a rapid and cost-effective diagnostic tool for confirmation of common β-thalassemia mutations in Malaysia.

Matched MeSH terms: beta-Thalassemia/ethnology; beta-Thalassemia/genetics*

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