Hb H Disease Among Tunisians: Molecular Characterization of α‐Thalassemia Determinants and Hematological Findings

Zorai, Amine; Alsuwaidan, Salem; Préhu, Claude; Omar, Souheil; Gérard, Nathalie; Hafsia, R; Bouaziz, Asma; Guémira, Fethi; Dellagi, K

doi:10.1081/hem-120018439

Cited by 10 publications

(4 citation statements)

References 15 publications

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“…It was only described in Greece in the Mediterranean area, the United Arab Emirates, and Iran at less than 1% of gene frequency . In this study, we report one case of this variant associated with the – MED‐I deletion that shows 17.4% of Hb H. In the Tunisian population, a similar average rate (17.66%) was observed with the α Saudi α/α Saudi α genotype . In fact, an important hemolysis is described in Hb H disease in association with the Hb Constant Spring .…”

Section: Discussionsupporting

confidence: 58%

“…Some sporadic cases of rare Hb variants were, however, described by different authors who used the protein sequencing procedure . During the last few years, molecular approach based on DNA technology allowed the description of both α‐ and β‐thalassemia spectra . By the same way, a certain number of rare abnormal variants (even unobserved at the protein level) were highlighted.…”

Section: Discussionmentioning

confidence: 99%

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Rare hemoglobin variants in Tunisian population

Zorai

Moumni

Mosbahi

et al. 2014

Int J Lab Hematology

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S U M M A RYDuring the last 30 years, many studies concerning hemoglobinopathies were realized among Tunisians. More than twenty different thalassemic alleles were detected on the b-globin gene, and less are affecting the a-globin genes. Unusual hemoglobin (Hb) variants other than Hb S, Hb C, and Hb O-arab, which are the most frequent variants in Tunisia, were also detected. Eight Tunisian subjects were studied at phenotypic and molecular levels. Hematological indices and hemoglobin (Hb) pattern were performed by alkaline electrophoresis and isoelectric focusing (IEF), and the Hb fractions were quantitated by cation exchange HPLC. On genomic level, coding regions were amplified by polymerase chain reaction (PCR) followed by a sequencing of the purified PCR products using the dye terminator method. Seven uncommon Hb variants were detected and described for the first time among Tunisians. HbA2-Tunis [d46(CD5), Gly ? Glu, GGG ? GAG] is the newly described d-chain variant in our laboratory, and some other variants (Hb Constant Spring, G San Jose, and Hb J-Bangkok) are very uncommon in the Mediterranean region. We present here an updated review of the Hb variants detected among Tunisians. Twenty-one rare Hb variants were detected affecting the a1-, a2-, d-, c-, and b-globin genes, leading in some cases to a severe phenotype especially when the stability is completely altered. The ethnical history of Tunisia could explain this important variability of the observed rare Hb variants.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Rare hemoglobin variants in Tunisian population

Zorai

Moumni

Mosbahi

et al. 2014

Int J Lab Hematology

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“…Interestingly, the Mediterranean haplotypes α Nco I α and −α 20.5 found in Algeria are absent in neighboring Tunisia (14), whereas the α T-Saudi α poly A mutation found in Tunisia (18) was absent in all 306 chromosomes and also in 148 chromosomes from 74 recently analyzed newborns (data not shown). The α T-Saudi α poly A mutation has previously been described to be most prevalent in the eastern part of the Mediterranean area and in the Arabian Peninsula (19)(20)(21).…”

Section: Discussionmentioning

confidence: 70%

Molecular Basis of α-Thalassemia in Algeria

et al. 2008

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An epidemiological molecular study was carried out to evaluate the spectrum and allelic frequency of alpha-thalassemia (alpha-thal) defects in Algeria. A series of 153 randomly selected blood donors was screened for 10 alpha-thal alleles described in the Mediterranean area. In addition, six unrelated cases with hematological and biochemical data suggestive of Hb H disease were investigated. Our data revealed an allele frequency of 4.6%. The presence of alpha(0)-thal determinants (-alpha(20.5) and --MED I) was observed both in Hb H patients and in the randomly collected samples. Overall, the -alpha(3.7) deletion was the most prevalent allele (2.9%), followed by the alpha(Nco I)alpha (HBA2:c.1A>G) allele (0.6%) and by the alpha(Hph I)alpha (HBA2:c.95 + 2_95 + 6delTGAGG), -alpha(20.5), --(MED I) alleles (0.3% each). The -alpha(4.2) deletion was observed in only one Hb H patient. These results outline the heterogeneity of the alpha-thal alleles in Algeria which reflects the anthropological history of the country. Because of their frequency, alpha-thal alleles are probably frequent modulators of prevalent beta-globin gene-related hemoglobinopathies in Algeria.

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“…Many cases of HbH disease were documented worldwide (Chen et al, 2000;Kanavakis et al, 2000;Wenning et al, 2000;Liu et al, 2000;Waye et al, 2001;Higgs, 2001;Zorai et al, 2002Zorai et al, , 2003Eng et al, 2005;Li et al, 2005;Origa et al, 2006;Chan et al, 2007;Sura et al, 2007). Some cases of HbH diseases have been found in the newborn in West Bengal, and in Bombay, 2% and 4% of cord samples contained Hb Bart's (Chouhan et al, 1970;Mitra, 1983).…”

Section: Introductionmentioning

confidence: 92%

Molecular and Hematological Characterization of Hemoglobin H Disease in the Bengali Population of Kolkata, India

Dastidar

Gajra²,

De³

2011

Genetic Testing and Molecular Biomarkers

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This article reports the incidence of hemoglobin H (HbH) disease among the nontribe Bengali population living in South 24-Parganas of West Bengal. Among 105 patients with unexplained anemia with moderate hematological parameters referred to our laboratory over a period of 2 years, 17 cases (16.19%) were found to have HbH disease identified by hemoglobin electrophoresis. Molecular investigation for two common mutations of α-thalassemia (-3.7α, -4.2α) was carried out in these 17 cases using DNA extraction followed by multiplex polymerase chain reaction. Presence of these common mutations were identified in 10 of the 17 cases. Of them, -3.7α homozygotes (-3.7α/-3.7α), -3.7α/-4.2α double heterozygotes, and -4.2α homozygotes (-4.2α/-4.2α) were found in three, five, and one patient, respectively. The South East Asian (- -SEA) mutation was searched for in one Chinese patient because this mutation is very common among the Chinese population, and he showed the presence of this mutation. Seven patients with HbH disease did not show any of these mutations. These patients may have other α mutations, which need to be studied further. The need to screen for α-thalassemia at the molecular level in patients with unexplained anemia and its implication in the future generation of our society have been discussed in this article.

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Hb H Disease Among Tunisians: Molecular Characterization of α‐Thalassemia Determinants and Hematological Findings

Cited by 10 publications

References 15 publications

Rare hemoglobin variants in Tunisian population

Rare hemoglobin variants in Tunisian population

Molecular Basis of α-Thalassemia in Algeria

Molecular and Hematological Characterization of Hemoglobin H Disease in the Bengali Population of Kolkata, India

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