Clinical features and molecular analysis in Thai patients with HbH disease

We studied the α-globin gene abnormalities, the clinical features, hematologic values, growth assessment, transfusion therapy, and serum ferritin levels of patients with hemoglobin H (HbH) disease in southern Thailand. HbH disease in 83 of the 147 patients was the deletional type of HbH. The remaining 64 patients was the nondeletional type of HbH disease. All 83 patients with the deletional type were double heterozygotes of α⁰-thalassemia and α⁺-thalassemia. The Southeast Asian type of α⁰-thalassemia accounted for 98% of the Thai patients with HbH disease and the Thai type of α⁰-thalassemia made up the rest. A 3.7-kb deletion accounted for 91% of α⁺-thalassemia, and a 4.2-kb deletion made up the rest of the deletional type. In patients with nondeletional type of HbH disease, the Constant Spring variant was the majority of the disease. Newborns with a nondeletional genotype had higher mean corpuscular volume, had higher mean corpuscular hemoglobin, had higher red blood cell distribution width, had lower mean corpuscular hemoglobin concentration, and had higher proportions of Hb Bart's than those with a deletional genotype. Twenty-one percent of children with HbH disease had growth deficiency. A genotype–phenotype correlation was found; patients with the nondeletional type of HbH disease had more symptoms at a younger age, more severe hemolytic anemia, more growth deficiency, more dysmorphic facial features, larger spleens, larger livers, and higher serum ferritin levels and required more transfusions than patients with deletional HbH disease.     

Identification of Hb Q-India (64 Asp→His) in Thailand

More than 30 different hemoglobin variants either affecting  or β globin chains have been identified in Thailand. The large variety in the different forms of hemoglobinopathy contributes to several complicated interactions, since different types of defective globin alleles are prevalent in Thailand and nearly 30-40% of the population are carriers of either  or β thalassemia (thal). Many rare and novel abnormal globin variants in Thai subjects have been identified in our laboratory within the past few years; including Hb Lepore-Hollandia, homozygous Hb Tak, Hb Dhonburi, Hb G-Makassar, Hb G-Coushatta, Hb New York, Hb Paksè and Hb Pak Num Po. In addition to these, here we report, for the first time, the identification of Hb Q-India, an innocuous  globin variant, in a Thai family with Indian ancestry. This report highlights the complexity associated with identifying unknown globin variants within a population that has a heterogeneous repertoire of globin chain disorders.     

A rare association of alphaO-thalassemia (--SEA) and an initiation codon mutation (ATG-->A-G) of the alpha2 gene causes Hb H disease in Thailand

Several rare and hitherto unidentified non deletional alpha-thalassemias (alphaTalpha or alphaalphaT) have been reported from Thailand within the past few years. Interactions of these determinants with alphaO-thalassemia (thal) (--/), which is highly prevalent in this region, give rise to various genotypes (--/ alphaTalpha or --/alphaalphaT) underlying Hb H disease. We report herein the interaction of a rare initiation codon mutation of the alpha2 gene and alphaO-thal in a Thai boy with Hb H disease. This finding highlights a wide variety of molecular pathology of the alpha-globin genes underlying alpha-thal syndrome in Southeast Asia.     

Common origin of a rare beta-globin initiation codon mutation (ATG-->AGG) in Asians

In this report, we describe two Thai siblings presenting with mild hypochromic microcytic anaemia and splenomegaly since 2(1/2) years of age. However, both patients were otherwise well with normal weight and height development and did not require transfusion during the 6-year follow-up period. Haematological and haemoglobin analyses were consistent with the clinical diagnosis of Hb E/beta-thalassaemia disease. To provide proper genetic counselling for this family, a definitive diagnosis of beta-thalassaemia was achieved using molecular analysis. We identified a rare initiation codon mutation (ATG-->AGG) of the beta-globin gene in combination with the Hb E mutation (codon 26: GAG-->AAG). The initiation codon mutation has previously been reported in several East Asian populations but has never been found in Southeast Asia and in combination with Hb E before. The haplotype analysis revealed a common origin of this mutation in the Asian population (5': - + - + + - +: 3', type IV with framework 3 according to Orkin S, et al.). Although this rare mutation abolished the beta-globin expression and was considered as beta(0)-thalassaemia, the relatively mild phenotype in our patients may be attributed to a strong association between this mutation and the -158 (G)gamma (C-->T) polymorphism, an XmnI cleavage site (+), resulting in a high propensity of postnatal gamma-globin expression and ameliorating the clinical phenotypes.     

Identification of Hb Q-India (alpha64 Asp-->His) in Thailand

More than 30 different hemoglobin variants either affecting alpha or beta globin chains have been identified in Thailand. The large variety in the different forms of hemoglobinopathy contributes to several complicated interactions, since different types of defective globin alleles are prevalent in Thailand and nearly 30-40% of the population are carriers of either alpha or beta thalassemia (thal). Many rare and novel abnormal globin variants in Thai subjects have been identified in our laboratory within the past few years; including Hb Lepore-Hollandia, homozygous Hb Tak, Hb Dhonburi, Hb G-Makassar, Hb G-Coushatta, Hb New York, Hb Paksè and Hb Pak Num Po. In addition to these, here we report, for the first time, the identification of Hb Q-India, an innocuous alpha globin variant, in a Thai family with Indian ancestry. This report highlights the complexity associated with identifying unknown globin variants within a population that has a heterogeneous repertoire of globin chain disorders.     

Hb Woodville, a rare alpha-globin variant, caused by codon 6 mutation of the alpha1 gene

Since 1995, the national programme for the prevention and control of severe thalassaemia has been implemented in Thailand. This programme is composed of the population screening in pregnant women and couples by osmotic fragility, HbE screening and the confirmation test using haemoglobin analyses by electrophoresis or chromatography. Thereafter, several hitherto unidentified haemoglobins (Hbs) with structural defects are increasingly described and these variants are now easily studied using DNA technology. In this study, the authors describe the haematology and molecular analyses in a 28-yr-old healthy female who was identified as having an exceptionally 'high HbA2' from haemoglobin analysis. Subsequent analyses demonstrated that observed atypical 'HbA2' was, in fact, a rare innocuous alpha-globin variant, called Hb Woodville [alpha 2 6(A4); Asp --> Tyr]. For the first time, this abnormal Hb species is characterised at the molecular level.     

Prevalence of HFE mutations among the Thai population and correlation with iron loading in haemoglobin E disorder

Co-inheritance of HFE mutations has a substantial role in iron overload in beta-thalassaemia carriers in north European populations where two HFE mutations, C282Y and H63D, are prevalent. In Thailand, there was little information about the allele frequency of HFE mutations. It is of interest to determine whether such determinants represent a potential risk in developing iron overload as nearly 40% of the Thai population carry either one of thalassaemia or haemoglobinpathy alleles. A total of 380 normal controls from five different regions including Bangkok were screened for the HFE C282Y, H63D and IVS5+1 G-->A alleles. In addition, 70 individuals with homozygous haemoglobin E (Hb EE) were also tested and their genotypes were correlated with levels of serum ferritin. H63D is the major HFE mutation found in the Thai population with an average allele frequency of 3% (range 1-5%). One individual was heterozygous for the splice site mutation IVS5 + 1 G --> A, and the C282Y allele was not detected. In the Hb EE group, five individuals had iron deficiency (ferritin <12 microg/L) and the remaining 65 individuals had a wide range of serum ferritin levels of 16-700 microg/L. Four individuals with Hb EE were heterozygous for the H63D allele. No significant difference in serum ferritin level was detected in this group with or without the HFE mutation (137.2 +/- 78 vs. 116.3 +/- 128 microg/L). HFE mutations are relatively uncommon among the Thai population, and the average allele frequency of the ancient H63D mutation is similar to that of other countries in this region. Because of their paucity, it appears that these alleles are less likely to be responsible for high ferritin levels and iron loading in individuals with Hb E related disorders.     

Two independent origins of Hb Dhonburi (Neapolis) [beta 126 (H4) Val-->Gly]: an electrophoretically silent hemoglobin variant

BACKGROUND: A beta-hemoglobin variant (beta 126 (H4) Val-->Gly) was reported from Thailand and Naples (Southern Italy) as Hb Dhonburi (1) and Hb Neapolis (2), respectively. This abnormal hemoglobin, resulting from a valine to glycine substitution in the contact region between alpha and beta subunits, gives rise to instability at non-physiological conditions. However, it was difficult to distinguish this variant from Hb A using hemoglobin electrophoresis and cation exchange liquid chromatography. Hb Dhonburi was rarely reported, possibly due to a relatively milder phenotype in heterozygote with slightly decreased MCV. Thus several Hb Dhonburi carriers might have been under-diagnosed. METHODS: Combined molecular analyses by PCR-single strand conformation polymorphism (PCR-SSCP) and direct genomic sequencing of the beta globin genes were carried out in 2 pediatric patients with mild thalassemia intermedia. A novel amplification refractory mutation system (ARMS-PCR) was developed and performed in five individuals with microcytosis and borderline Hb A(2). RESULTS: Both patients were compound heterozygotes for Hb E and Hb Dhonburi. In addition, 5 Hb Dhonburi heterozygotes, including 3 identified through thalassemia carrier screening, were identified by ARMS-PCR. Linkage analysis of the affected families revealed that the haplotype of Hb Dhonburi in Thailand (VII) was different from that of Hb Neapolis (V) suggesting 2 independent mutational events. CONCLUSIONS: The molecular strategy described provides a robust and economical measure, alternative to the whole beta globin genes sequencing, to identify rare or unknown beta globin mutations. To overcome its 'silent' nature on electrophoresis, we proposed a novel ARMS-PCR for a rapid diagnosis of Hb Dhonburi in future cases.     

Effects of elastic taping,non-elastic taping and static stretching on recovery after intensive eccentric exercise

The purpose of this study was to compare the effect of elastic tape (Kinesio tape) to placebo tape or static stretching on delayed onset muscle soreness. Fifty-one untrained female healthy volunteers were randomly assigned into three groups (n = 17/group), elastic tape, placebo tape and stretching group. Muscle soreness was induced by 4 sets of 25 maximal isokinetic (60°.s^?1) eccentric contractions of dominant quadriceps on an isokinetic dynamometer. Compared with placebo tape, the elastic tape participants had less muscle soreness at 72 h post-exercise (p = 0.01). The elastic tape also increased isometric strength at 72 h post-exercise compared with the placebo (p = 0.03) and stretching group (p = 0.02). However, there was little effect between groups for changes in thigh circumference, jumping, pressure pain threshold, rate of perceived exertion, creatine kinase activity and joint motion. Elastic taping increased muscle strength recovery and reduced muscle soreness after intensive exercise.