A large cohort of Hb H disease in northeast Thailand: A molecular revisited, diverse genetic interactions and identification of a novel mutation.

Background And Aims: To update the molecular characteristics of α-thalassemia in northeast Thailand, the molecular basis and genetic interactions of Hb H disease were examined in a large cohort of patients.

Materials And Methods: A study was done on 1,170 subjects with Hb H disease and various genetic interactions encountered during 2009-2023. Hb and DNA analyses were carried out.

A large cohort of deletional high hemoglobin F determinants in Thailand: A molecular revisited and identification of a novel mutation.

Background And Aims: High hemoglobin F determinants can be classified into hereditary persistence of fetal hemoglobin (HPFH) and δβ-thalassemia with different phenotype. We report the molecular basis and hematological features in a large cohort of deletional high Hb F determinants in Thailand.

Materials And Methods: Subjects (n = 28,177) encountered during 2015-2022 were reviewed, and those with phenotypically suspected of having high Hb F determinants were selected.

Anemia in an ethnic minority group in lower northern Thailand: A community-based study investigating the prevalence in relation to inherited hemoglobin disorders and iron deficiency.

Background: Anemia is a globally well-known major public health problem. In Southeast Asia where there is ethnic diversity, both iron deficiency (ID) and inherited hemoglobin disorders (IHDs) are prevalent and are considered to be the major factors contributing to anemia. However, little is known about the anemia burden among the ethnic minorities.

Prospective screening for δ-hemoglobinopathies associated with decreased hemoglobin A levels or hemoglobin A variants: A single center experience.

Background: δ-hemoglobinopathies may lead to misdiagnosis of several thalassemia syndromes especially β-thalassaemia carrier, it is important to evaluate the δ-globin gene defects in areas with high prevalence of globin gene disorders. We describe a prospective screening for δ-hemoglobinopathies in a routine setting in Thailand.

Methods: Study was done on a cohort of 8,471 subjects referred for thalassemia screening, 317 (3.

Molecular basis of a high Hb A/Hb F-thalassemia trait: a retrospective analysis, genotype-phenotype interaction, diagnostic implication, and identification of a novel interaction with -globin gene triplication.

Background: -thalassemia deletion removing 5´-globin promoter usually presents phenotype with high hemoglobin (Hb) A and Hb F levels. We report the molecular characteristics and phenotype-genotype correlation in a large cohort of the -thalassemia with 3.4 kb deletion.

Frequency of unnecessary prenatal diagnosis of hemoglobinopathies: A large retrospective analysis and implication to improvement of the control program.

Objective: To determine the frequency and etiology of unnecessary prenatal diagnosis for hemoglobinopathies during 12 years of services at a single university center in Thailand.

Methods: We conducted a retrospective cohort analysis of prenatal diagnosis during 2009-2021. A total of 4,932 couples at risk and 4,946 fetal specimens, including fetal blood (5.

Loop-mediated isothermal amplification (LAMP) colorimetric phenol red assay for rapid identification of α0-thalassemia: Application to population screening and prenatal diagnosis.

Background: Identification of α0-thalassemia (SEA and THAI deletions) is essential in preventing and controlling of severe thalassemia diseases. We have developed the LAMP colorimetric assays for the detection of these two thalassemia defects and validated them in population screening and prenatal diagnosis.

Methods: Three LAMP colorimetric assays specific for α0-thalassemia (SEA deletion), α0-thalassemia (THAI deletion) and normal DNA sequence were developed.

α-thalassemia in affected fetuses with hemoglobin E-β-thalassemia disease in a high-risk population in Thailand.

Objectives: A co-inheritance of α-thalassemia can ameliorate the clinical severity of the hemoglobin (Hb) E-β-thalassemia disease. This information should be provided at prenatal diagnosis. Identification of α-thalassemia in an affected fetus is therefore valuable.

Diagnostic value of fetal hemoglobin Bart's for evaluation of fetal α-thalassemia syndromes: application to prenatal characterization of fetal anemia caused by undiagnosed α-hemoglobinopathy.

Background: To evaluate whether the quantification of fetal hemoglobin (Hb) Bart's is useful for differentiation of α-thalassemia syndromes in the fetus and to characterize the fetal anemia associated with fetal α-hemoglobinopathy.

Methods: A total of 332 fetal blood specimens collected by cordocentesis were analyzed using capillary electrophoresis and the amount of Hb Bart's was recorded. The result was evaluated against thalassemia genotypes determined based on Hb and DNA analyses.

Direct PCR assays without DNA extraction for rapid detection of hemoglobin Constant Spring and Pakse' genes: application for carrier screening and prenatal diagnosis.

Hemoglobin Constant Spring (Hb CS) and Hb Pakse' (PS) are the common non-deletional α-thalassemia found in Thailand. These two variants can cause severe thalassemia syndromes, especially in fetus and neonate. Molecular diagnosis is the only confirmatory method because Hb CS and Hb PS are usually missed by routine screening and Hb analysis.

β-Hemoglobinopathies in the Lao People's Democratic Republic: Molecular diagnostics and implication for a prevention and control program.

Introduction: A high frequency of β-thalassemia in Lao People's Democratic Republic necessitates the importance of complete molecular data before a prevention and control program could be established. Limited data are available for Lao PDR. We have now reported an extended information on the molecular basis of β-hemoglobinopathies in this population.

Thalassemia and erythroid transcription factor mutations associated with borderline hemoglobin A in the Thai population.

Introduction: Elevated hemoglobin (Hb) A is an important diagnostic marker for β-thalassemia carriers. However, diagnosis of cases with borderline Hb A may be problematic. We described the molecular characteristics found in a large cohort of Thai subjects with borderline Hb A.

A novel SNP rs11759328 on Rho GTPase-activating protein 18 gene is associated with the expression of Hb F in hemoglobin E-related disorders.

Hemoglobin (Hb) F has a modulatory effect on the clinical phenotype of β-thalassemia disease. High expression of Hb F in Hb E-related disorders has been noted, but the mechanism is not well understood. We have examined the association of a novel SNP rs11759328 on ARHGAP 18 gene and other known modulators with a variability of Hb F in Hb E-related disorders.

Molecular basis of Hb H and AEBart's diseases in the Lao People's Democratic Republic.

Introduction: As compared to other neighboring countries, limited information on α-thalassemia diseases is available for Lao PDR. We reported for the first time a genetic diversity associated with Hb H and AEBart's diseases in Laos patients.

Methods: Study was done on Laos patients with Hb H disease (n = 14) and AEBart's disease (n = 14) whose blood specimens were transferred to our laboratory for the investigation of thalassemia.

Molecular Survey of Hemoglobinopathies in Myanmar Workers in Northeast Thailand Revealed an Unexpectedly High Prevalence of α-Thalassemia.

To provide the molecular information on hemoglobinopathies in the Myanmar population, the study was carried out on Myanmar workers in Khon Kaen Province in northeast Thailand. A total of 300 anonymous Myanmar factory workers were randomly recruited during their annual medical checkup. Hemoglobinopathies were identified using hemoglobin (Hb) and DNA analyses.

Molecular Characteristics of Hb New York [β113(G15)Val→Glu, HBB: c.341T>A] in Thailand.

Hb New York or Hb Kaohsiung [β113(G15)Val→Glu (GTG>GAG), HBB: c.341T>A] has been considered a rare β hemoglobin (Hb) variant found originally in an Iranian woman and later in diverse populations but its genetic origin has not been elucidated. Here we report molecular and hematological descriptions of this variant found in the Thai population.

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

Objectives: 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 α-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).

A large cohort of hemoglobin variants in Thailand: molecular epidemiological study and diagnostic consideration.

Background: Hemoglobin (Hb) variants are structurally inherited changes of globin chains. Accurate diagnoses of these variants are important for planning of appropriate management and genetic counseling. Since no epidemiological study has been conducted before, we have investigated frequencies, molecular and hematological features of Hb variants found in a large cohort of Thai subjects.

ARKRAY ADAMS A1c HA-8180T Analyzer for Diagnosis of Thalassemia and Hemoglobinopathies Common in Southeast Asia.

Objective: To evaluate the ARKRAY ADAMS A1c HA-8180T analyzer for diagnosis of thalassemias and hemoglobinopathies commonly found in the Southeast Asian population.

Methods: Our cohort consisted of 557 specimens from adults referred for thalassemia diagnosis. From these, we selected 457 specimens and subjected them to DNA analysis to determine various thalassemia genotypes.

Association of Hb Thailand [α56(E5)Lys→Thr] and Hb Phnom Penh [α117(GH5)-Ile-α118(H1)] with α(0)-thalassemia: molecular and hematological features and differential diagnosis.

We report the molecular and hematological characteristics of two rare hemoglobin (Hb) variants found in associations with a common α(0)-thalassemia (α(0)-thal) in Thai patients. The first case (P1) was a generally healthy 27-year-old man discovered during our ongoing thalassemia screening program. Hemoglobin and DNA analyses identified a previously undescribed condition of compound heterozygosity for Hb Thailand [α56(E5)Lys→Thr] and α(0)-thal (SEA deletion).

Phenotypic expression of hemoglobins A₂, E and F in various hemoglobin E related disorders.

Study on the phenotypic expression of hemoglobin (Hb) A(2) and Hb E in Hb E disorders has been difficult due to the co-separation of Hb A(2) and Hb E in most Hb analysis assays. Because these two Hbs are separated on capillary electrophoresis, we studied phenotypic expression of Hbs A(2), E and F in various Hb E disorders using this system. This was done on 362 subjects with several Hb E disorders including heterozygous Hb E, homozygous Hb E, β-thalassemia/Hb E, δβ-thalassemia/Hb E, and Hb Lepore/Hb E and those of these disorders with several forms of α-thalassemia.

Complex interaction of hemoglobin (Hb) Nakhon Ratchasima [α63(E12)Ala→Val], a novel α2-globin chain variant with Hb E [β26(B8)Glu→Lys] and a deletional α(+)-thalassemia.

Objectives: To describe the hematological and molecular features as well as diagnostic aspects of a complex hemoglobinopathy caused by interaction of a novel α2-globin chain variant with hemoglobin (Hb) E and α(+)-thalassemia.

Methods: Blood specimen of a 41-yr-old Thai man was transferred to our center for the analysis of unknown Hb variant. Hb analysis was carried out using automated high-performance liquid chromatography (HPLC) and capillary electrophoresis system.

Hb Phimai [β72(E16)Ser→Thr]: a novel β-globin structural variant found in association with Hb constant spring in pregnancy.

A Thai pregnant woman with α and β hemoglobinopathies is described. Initial hemoglobin (Hb) analysis revealed an unknown variant with a high performance liquid chromatography (HPLC) elution pattern similar to Hb Hope [β136(H14)Gly→Asp]. Subsequent DNA-based diagnostics revealed that she was a carrier of Hb Constant Spring [Hb CS, α142, TAA>CAA (α2)] and a novel β-globin chain variant [β72(E16)Ser→Thr, AGT>ACT] which we named Hb Phimai.

Thalassemia and hemoglobinopathies in Southeast Asian newborns: diagnostic assessment using capillary electrophoresis system.

Background: We have investigated the Capillarys 2 Hemoglobin testing system to assist in presumptive diagnosis of thalassemia and hemoglobinopathies commonly found in Southeast Asia.

Methods: Study was conducted on 226 newborns. Hematological parameters were recorded and Hb profiles were examined on the Capillarys 2 Hemoglobin analyzer (SEBIA).

Interactions of hemoglobin Lepore (deltabeta hybrid hemoglobin) with various hemoglobinopathies: A molecular and hematological characteristics and differential diagnosis.

Hemoglobin (Hb) Lepore is a variant consisting of two alpha-globin and two deltabeta-globin chains. In heterozygote, it is associated with clinical findings of thalassemia minor but interactions with other hemoglobinopathies can lead to various clinical phenotypes. Using a combination of Hb-HPLC, Hb-capillary electrophoresis and DNA analyses, we have identified 14 patients with Hb Lepore-Hollandia including eight heterozygotes, two double heterozygotes with alpha(+)-thalassemia, two compound heterozygotes with Hb E (initially diagnosed as Hb E-beta-thalassemia) and two previously undescribed conditions of double heterozygote for Hb Lepore/Hb Constant Spring and Hb Lepore/alpha(0)-thalassemia, both associated with higher levels of Hb F and lower levels of Hb Lepore.