Hb Athens-Georgia (beta 40(C6) Arg > Lys, HBB:c.122G > A) with a single α-globin gene (Hb H disease) in a Thai family: molecular, hematological, and diagnostic aspects

In a previous study, we described a form of nondeletion alpha- thalassemia (alpha T Saudi alpha) found in subjects of Saudi Arabian origin. In the current study, using synthetic oligoprobe hybridization and restriction enzyme analysis, we have demonstrated that the molecular basis of alpha T Saudi alpha is due solely to a single base mutation (AATAAA----AATAAG) in the polyadenylation signal of the alpha 2 gene and that the frameshift mutation in codon 14 of the linked alpha 1 gene is the result of a cloning artefact. The alpha 2 polyadenylation signal mutation occurs in other Middle Eastern and the Mediterranean populations and is responsible for the clinical phenotype of Hb H disease in some Saudi Arabian individuals with five alpha genes (alpha T Saudi alpha/(alpha alpha alpha)T Saudi). Evidence suggests that the (alpha alpha alpha)T Saudi haplotype has arisen as a result of a recombination between two misaligned chromosomes bearing the alpha T Saudi alpha defect.

Download Full-text

Clinical Features and Molecular Analysis of Hb H Disease in Taiwan

BioMed Research International ◽

10.1155/2014/271070 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5

Author(s):

Yu-Hua Chao ◽

Kang-Hsi Wu ◽

Han-Ping Wu ◽

Su-Ching Liu ◽

Ching-Tien Peng ◽

...

Keyword(s):

Clinical Features ◽

Globin Gene ◽

Clinical Manifestations ◽

Clinical Severity ◽

Blood Transfusions ◽

Limited Data ◽

Phenotype Correlation ◽

Younger Age ◽

Hb H Disease ◽

Thalassemia Mutation

Thalassemia is highly prevalent in Taiwan, but limited data are available about the association between genotypes and clinical manifestations in Taiwanese patients with Hb H disease. Here, we studied α-globin gene abnormalities and clinical features in Taiwanese patients with Hb H disease. Of the 90 patients, sixty-four (71.1%) were deletional and twenty-six (28.9%) were nondeletional Hb H disease. The (- -SEA) type ofα0-thalassemia mutation was detected in the majority of patients (>95%). The most common genotype was (- -SEA/-α3.7), followed by (- -SEA/αcsα). After further investigation of the genotype-phenotype correlation in 68 patients, we found that patients with nondeletional Hb H disease had more severe clinical features than those with deletional Hb H disease, including younger age at diagnosis, more requirement of blood transfusions, and larger proportion of patients with splenomegaly, hepatomegaly or jaundice. This is probably a consequence of the lower hemoglobin levels and the higher Hb H levels. The clinical severity was highly variable even among patients with an identical genotype, and the diversity was much more profound among patients with (- -/αcsα) genotype. Therefore, predicting the phenotype directly from the genotype in Hb H disease remains relatively difficult in Taiwan.

Download Full-text

An alpha-2 Globin Gene Initiation Codon Mutation in a Vietnamese Patient with Hb H Disease

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1998.tb10502.x ◽

1998 ◽

Vol 850 (1 COOLEY'S ANEM) ◽

pp. 398-400

Author(s):

F. KUTLAR ◽

T. V. ADAMKIEWICZ ◽

R. B. MARKOWITZ ◽

L. HOLLEY ◽

A. KUTLAR

Keyword(s):

Globin Gene ◽

Initiation Codon ◽

Hb H Disease ◽

Codon Mutation

Download Full-text

First Report of a Case with Nondeletional Hb H Disease Caused by IVS-I-116 (A>G) of the α2-Globin Gene

Hemoglobin ◽

10.1080/03630269.2018.1556684 ◽

2018 ◽

Vol 42 (5-6) ◽

pp. 344-346

Author(s):

Xiao-Hong He ◽

Rui Zhang ◽

Guang-Xing Mai ◽

Li-Rong Ren ◽

Dong-Zhi Li

Keyword(s):

Globin Gene ◽

First Report ◽

Hb H Disease

Download Full-text

Prolonged Pyrexia: Kikuchi-Fujimoto Disease in a Patient With Hb H-Constant Spring Thalassemia

Clinical Medicine Insights Case Reports ◽

10.1177/1179547620936424 ◽

2020 ◽

Vol 13 ◽

pp. 117954762093642

Author(s):

Ganesh Kasinathan

Keyword(s):

Dna Analysis ◽

Complete Blood Count ◽

Globin Gene ◽

Oral Prednisolone ◽

Lymph Node Biopsy ◽

Whole Body ◽

Gene Deletions ◽

Prolonged Fever ◽

Alpha Globin ◽

Hb H Disease

Introduction: Haemoglobin H (Hb H) disease is an alpha thalassemia characterised by either 3 alpha-globin gene deletions (deletional type) or 2 alpha-globin gene deletions with 1-point mutation (nondeletional type). Haemoglobin H-Constant Spring thalassemia is the most common Hb H disease in Asia. Kikuchi-Fujimoto disease (KFD) is an important cause of prolonged fever in thalassemia and is often self-limiting. Case Presentation: A 30-year-old women of Malay ethnicity presented to the thalassemia unit with a month history of prolonged fever, headache, and painful enlarged neck lymph nodes. She is known to have Hb H-Constant Spring thalassemia, in which she is on 3-monthly blood transfusion. Physical examination revealed persistent pyrexia of 38°C. She had multiple tender bilateral cervical lymphadenopathies with the largest measuring 4 × 4 cm. The complete blood count revealed hypochromic microcytic anaemia with leucopenia and a normal platelet count. She had hyperferritinemia of 3500 ng/mL. The DNA analysis of alpha-globin gene showed heterozygosity for alpha zero thalassemia South East Asian deletion with termination codon mutation (TAA-CAA) which was consistent with Hb H-Constant Spring thalassemia. Numerous investigations for her prolonged fever including cultures did not yield any positive results. Whole-body computed tomography (CT) imaging showed diffuse lymphadenopathies and hepatosplenomegaly. Finally, a left cervical lymph node biopsy was performed which was consistent with KFD. She was treated with oral prednisolone which was gradually tapered based on response. Currently, she is asymptomatic and is in complete remission. Conclusion: Kikuchi-Fujimoto disease should be considered as a cause for prolonged pyrexia in a patient with thalassemia. An early diagnosis of KFD would avoid an unnecessary battery of investigations. This case highlights the importance of clinicopathological correlation in managing patients with thalassemia as these patients often have other associated morbidities.

Download Full-text

An Entirely Novel Form of α Thalassemia in Patients from the South Pacific Linked to Chromosome 16.

Blood ◽

10.1182/blood.v106.11.2688.2688 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2688-2688

Author(s):

Vip Viprakasit ◽

Marco De Gobbi ◽

Helena Ayyub ◽

Ioannis Ragoussis ◽

William G. Wood ◽

...

Keyword(s):

Iron Status ◽

Globin Gene ◽

Restriction Enzymes ◽

Regulatory Elements ◽

Pacific Islanders ◽

Pulse Field ◽

Specific Gene ◽

Globin Genes ◽

Chromosome 16 ◽

Hb H Disease

Abstract Although a great deal is known about the molecular mechanism underlying α thalassemia (thal), which is characterized by reduced or absent α-globin expression, the molecular basis of α thalassemia in Pacific Islanders is not fully understood. Previously single α gene deletion alleles (−α3.7 and −α4.2) were the only types of α thalassemia identified in this population, however these genotypes do not account for several cases of Hb H disease in the Melanesian Islanders of Papua New Guinea (PNG) and Vanuatu. To date, no mutations have been found in the α globin gene cluster of these individuals. To determine the cause of α thalassemia in this population, we studied 35 individuals from three unrelated families of Pacific Islanders. 16 of them had classical Hb H disease characterized by mild to moderate anemia (Hb; 10.3 ± 2.3 g/dL), microcytosis (MCV; 66 ± 3.5 fL), hypochromia (MCH; 19.8 ± 1.6 pg), positive Hb H by electrophoresis (5–18%) and numerous Hb H inclusion bodies in peripheral blood. Gene mapping revealed that six had normal genotypes (αα/αα) while the rest were heterozygotes for α+ thalassemia (−α/αα). Preliminary sequence analyses demonstrated that the α globin genes and their regulatory elements were entirely normal casting some doubt on whether this novel form of α thal is genuinely linked to chromosome 16. Using a combination of a long range haplotype analysis by MALDI-TOF to simultaneously genotype 80 SNPs covering 350 kb of the telomeric end of chromosome 16 (16p; 13.3) and several tandem repeat markers (VNTRs and HVRs), we demonstrated that the α thal phenotype is strongly associated with a single haplotype (IIIa;PNG) found in these cases. Consistent with the Hb H patients, individuals from these families and another 15 unrelated individuals (4.7%) identified in a population survey (n = 315) who were hypochromic (MCH < 25 pg), despite having normal α genes (αα/αα) and iron status, were also found to carry the same type of chromosome 16 linked to the affected haplotype. These findings indicate that this form of α thalassemia is unequivocally linked to chromosome 16. Subsequent linkage disequilibrium analysis (LD) in these cases limited the chromosomal interval containing the mutation to within 169 kb from the 16p-telomere. Extensive genomic mapping using more than 10 restriction enzymes and 37 plasmid and PCR probes together with Pulse Field Gel Electrophoresis (PFGE), covering 400 kb of 16p, excluded small deletions, insertions, rearrangements and chromosomal truncations in the affected segment of chromosome 16. Direct genomic sequencing of collectively 40 kb of the α globin genes, all known multispecies conserved sequences (MCS-R, 1–4) demonstrated no apparent mutation. Interestingly, interspecific somatic cell hybrid analysis of the affected chromosome 16 in a mouse erythroid leukemia (MEL) background did not recapitulate the phenotype of α thalassemia. These results suggest a novel mechanism, either at the genetic or epigenetic level, underlying the reduced expression of the α globin genes in the Pacific Islanders and understanding such mechanism might provide more insights on the complexity of stage- and tissue-specific gene regulation in human erythroid environment.

Download Full-text

A novel single gene deletion (-αMAL3.5) giving rise to silent α thalassemia carrier removing the entire HBA2 gene observed in two Chinese patients with Hb H disease: case report of two probands

Thalassemia Reports ◽

10.4081/thal.2015.4675 ◽

2015 ◽

Vol 5 (1) ◽

Author(s):

Faidatul Syazlin Abdul Hamid ◽

Rahimah Ahmad ◽

Mohamed Saleem ◽

Nur Aisyah Aziz ◽

Syahira Lazira Omar ◽

...

Keyword(s):

Dna Analysis ◽

Single Gene ◽

Globin Gene ◽

Clinical Findings ◽

Chinese Patients ◽

Hematological Indices ◽

Disease Case ◽

Pcr Multiplex ◽

Hb H Disease ◽

Pcr Method

We report a novel deletion at the HBA2 presented with Hb H disease in two Malaysian- Chinese patients. The two unrelated probands were diagnosed with Hb H disease in a primary hematological screening for thalassemia. Results from routine molecular analysis with gap-polymerase chain reaction (PCR) method revealed a genotype asynchrony with the observed clinical presentation. Subsequent DNA analysis using a battery of molecular methods such as gap-PCR, multiplex ligation dependent probe amplification, DNA sequencing, confirmed the presence of a novel deletion in both the index cases removing the entire α2 globin gene. We have designated the deletion as (‒αMAL3.5). Hematological indices and clinical findings suggest that the deletion has an α+ phenotype. The molecular process of this deletion is the result from misalignment and unequal crossover event between the duplicated homologous Y-boxes within the α globin gene cluster. Uncharacterized deletions, single nucleotide polymorphism and other nucleotide indels at the primer binding sites may impede the optimum condition for its annealing and extension and therefore may invalidate the gap-PCR obscuring the real genotype. 我们报告了两例马来西亚华裔患者中随HbH病表现出的一种HBA2的新型缺失。这两例不相关的先证者在地中海贫血的初步血液筛查中被诊断出患有HbH病。采用跨越断裂点聚合酶链反应（PCR）方法进行常规分子分析的结果显示出一种与观察到的临床表现不一致的基因型。后续采用一系列分子方法（如跨越断裂点PCR、多重连接探针扩增、DNA测序）进行的DNA分析证实了这两个指示病例中的新型缺失的存在消除了整个α2珠蛋白基因。我们将该缺失命名为（-αMAL3.5）。血液学指标和临床结果提示该缺失具有α+表型。这种缺失的分子过程是α珠蛋白基因簇内部重复的同源Y-盒之间之间错配和不等交换事件的结果。未表征的缺失、单核苷酸多态性和其它核苷酸插入/缺失的引物结合位点可能阻碍其退火和延伸的最佳条件，因此可能使跨越断裂点PCR无效，模糊了真实的基因型。

Download Full-text

Atypical Hemoglobin H Disease Due to Compound Heterozygosity for -α3.7 and --SEA Deletions and Heterozygosity for the β-Chain Variant Hemoglobin Raleigh (β1 VAL→ALA).

Blood ◽

10.1182/blood.v106.11.3849.3849 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3849-3849

Author(s):

Ferdane Kutlar ◽

Mary Ann Knovich ◽

Dedrey Elam ◽

Daniel B. Jobe ◽

David H. Buss ◽

...

Keyword(s):

Globin Gene ◽

Oxygen Affinity ◽

Microcytic Anemia ◽

Low Oxygen ◽

Exertional Dyspnea ◽

Hb S ◽

Hb H Disease ◽

Β Chain ◽

Chain Variant ◽

Hb C

Abstract The co-existence of Hemoglobin H (Hb H) disease and heterozygosity for β-chain structural variants is a rare occurrence. Hb H disease has been reported in conjunction with Hb E, Hb C, Hb S, and Hb Hamilton. The combination of Hb H disease with Hb C and Hb S reportedly results in a mild hemolytic anemia without detectable Hb H. We present a new case of atypical Hb H disease that was also heterozygous for the rare β-chain variant Hb Raleigh. The patient is a 27-year-old Cambodian female referred for the evaluation of microcytic anemia unresponsive to iron. She had a lifelong history of generalized fatigue, exertional dyspnea, and weakness in her legs. Physical exam was unremarkable except for pallor of mucuous membranes. There was no hepatosplenomegaly. She had a Hb of 9.7, HCT 30.8, MCV 56, MCH 17.6, MCHC 31.5, ferritin 92. Hb analysis on IEF revealed Hb A, Hb A2, and an abnormal band slightly more anodic to Hb A. No Hb H was observed. On cation exchange HPLC, she had 49.7% Hb A, 48.1% Hb X, and 2.2% Hb A2. Reverse phase HPLC revealed a βx chain eluting immediately before βA. Oxygen affinity was slightly reduced. PCR amplification and sequencing of the β-globin gene revealed heterozygosity for Hb Raleigh (Exon 1, codon 1, GTG→GCG, VAL→ALA). The patient was also found to be a compound heterozygote for -α3.7 and --SEA deletions. This case represents a novel interaction of a structural β-chain variant with Hb H disease. Hb Raleigh has previously been reported in Caucasians and in two Swedish families. It has decreased oxygen affinity. This is the first report of this variant in a Cambodian population. The absence of any detectable Hb H likely results from the inability of variant β-chains to form a viable tetramer with a resultant decrease in βA. The low oxygen affinity did not negatively impact on the degree of anemia. This case, like some others reported previously, shows that the accurate diagnosis of Hb H disease in association with structural β-chain variants can be established by molecular methods, and the detection of Hb H on electrophoretic and chromatographic analyses may not always be reliable.

Download Full-text

Expression Profile of PIP Kinases During In Vitro Human Erythropoiesis

Blood ◽

10.1182/blood.v116.21.2079.2079 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2079-2079

Author(s):

Tânia Regina Zaccariotto ◽

Carolina Lanaro ◽

Dulcinéia Martins Albuquerque ◽

Magnun N N Santos ◽

Marcos André Cavalcanti Bezerra ◽

...

Keyword(s):

Gene Expression ◽

Cell Culture ◽

Expression Profile ◽

Expression Profiles ◽

Globin Gene ◽

Gene Expression Profiles ◽

Erythroid Differentiation ◽

Globin Genes ◽

Hb H Disease

Abstract Abstract 2079 Phosphatidylinositol phosphate kinases (PIPKs) are a family of lipid kinase enzymes that produce the second messenger PI4,5P2 (phosphatidylinositol 4,5-biphosphate), which plays an important role in the regulation of a variety of cellular activities, including gene expression. PIPKs are classified into 3 subfamilies — PIPK I (a, b, g), PIPK II (a, b, g) and PIPK III — which are functionally distinct and are located in different subcellular compartments. In a recent study in our laboratory, the PIPKIIa gene was differentially expressed in reticulocytes from 2 siblings with hemoglobin (Hb) H disease who had the same genotype (-a3.7/–SEA). Expression of both the PIPKIIa and b-globin genes were higher in the patient with the higher Hb H level, suggesting a possible relationship between PIPKIIa and the production of globins, particularly b-globin. In light of these findings, the aim of this study was to determine the gene expression profiles of PIPKs (I and II - with their isoforms a, b and g - and III) during erythropoiesis in peripheral blood hematopoietic CD34+ cell culture from 11 healthy volunteers and 6 patients with hemoglobinopathies [2 with a-thalassemia (Hb H disease), 2 with b-thalassemia (homozygous for the IVS-I-6-T-C mutation) and 2 with sickle cell anemia] using quantitative real time PCR (qRT-PCR) and to compare these profiles with the gene expression profiles of a-, b- and g-globins on the 7th, 10th and 13th days of the erythroid culture. In the cell culture from the normal group, expression of the PIPKIIa and other PIPK genes increased during erythroid differentiation, coinciding with the expression profiles of globin genes and showing in particular that a-globin has a significant effect on PIPKIIa (p<0.0001), as the PIPKIIa on a-globin gene (p=0.0002). In the patients, the expression profile of the PIPKIIa gene also increased during differentiation, whereas the results for the other PIPK genes varied. However, mRNA levels differed between patients, indicating greater complexity in individuals with hemoglobinopathies. PIPKIIa expression level was elevated in the culture from one of the a-thalassemia patients (approximately 12 times higher than in the corresponding control) but was lower than the control in one of the b-thalassemia patients. Expression levels of this gene also varied among sickle cell patients. This is the first study of the gene expression profiles of these kinases during in vitro human erythropoiesis. We identified a standard pattern of gene expression for PIPKs, and PIPKIIa in particular, a gradual increase in expression during erythroid differentiation, similar to the pattern for globin genes. This suggests that PI4,5P2, as an important secondary messenger involved in the regulation of gene expression, may play an important role in the regulation of globin gene expression and the normal process of Hb synthesis in red blood cells. Although our results varied between patients, highlighting the complexity of the regulatory systems involved in Hb production, they reinforce the hypothesis of a relationship between PIPKIIa and globin expression. This work was supported by FAPESP, CNPq and CAPES. Disclosures: No relevant conflicts of interest to declare.

Download Full-text