Variation in Hemoglobin A<sub>2</sub>

Vella, F.

doi:10.3109/03630267708999171

Cited by 17 publications

(4 citation statements)

References 103 publications

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“…In all cases, the mutation was associated with Haplotype I (----/++). This finding is very remarkable if we consider that the only comparable group of carriers reported until now consists of eight families from Eastern Europe, of which three were Jewish [Ranney et al, 1969;Vella et al, 1972;Boerma et al, 1974;de Jong and Went, 1974;Carter et al, 1975;Vella, 1977;Eliakim and Rachmilewitz, 1983]. In addition, this allele has been reported in sporadic observations: in a Dutch person [de Jong and Went, 1974], in a Greek from Turkey [Aksoy and Erdem, 1966;Boerma et al, 1974], in a single Black [Li et al, 1991], in a Canadian, and in a Canadian Indian [Boerma et al, 1974].…”

Section: Origin and Spread Of The Allelesmentioning

confidence: 92%

“…In Italy, it has already been found in a family from Catania [Li et al, 1991;Schilliro et al, 1991]. Moreover, extensive surveys failed to detect the allele in about 100,000 subjects from European countries [Vella, 1977]. The most likely hypothesis to explain the presence of this mutant in 11 out of 43 families from Basilicata, all living in a restricted area, could be a founder effect.…”

Section: Origin and Spread Of The Allelesmentioning

confidence: 99%

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Epidemiology of the delta globin alleles in southern Italy shows complex molecular, genetic, and phenotypic features

Angioletti

Lacerra

Gaudiano³

et al. 2002

Hum. Mutat.

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We characterized mutations and haplotypes of the delta-globin gene (HBD, MIM# 142000) in two regions of southern Italy. Mutations were discovered by screening for individuals with Hb A2<2%. In Basilicata, about 10,000 students were screened and 53 carriers in 43 unrelated families were diagnosed; in Campania, cases were referred through a routine thalassemia counseling service. Twelve alleles were detected. Four were novel variants [Hb A2-Metaponto (g.238C>A), Hb A2-Campania (g.302C>A), Hb A2-Lucania (g.393C>G), and Hb A2-Capri (g.443G>T)]. Hb A2-Lucania was not inherited but had arisen in the propositus. Two were novel mutations in the noncoding regions: the substitutions IVS2+6T>A, presumably affecting the splicing, and g.-126A>T in the GATA motif presumably affecting transcription. All novel alleles were found associated with haplotypes common in the Mediterranean area. The remaining six were alleles already described. The Hb A2-Yialousa (g.82G>T) was the most prevalent (42/63 families). Recurrent homologous crossing-over events have, most likely, linked this allele to Haplotypes IX (24 families), IV (10 families), or III (seven families). The ratio of Haplotypes IX:IV:III was about the same in the two regions. The rare allele Hb A2-NYU (g.39T>A) was found in 11 families from Basilicata associated with Haplotype I. All the 11 families lived in a restricted area extending from the Ionian Coast for 15 km along the Angri and Sinni Rivers. A founder effect most probably gave origin to this isolated group. The remaining four alleles were rare: the 7.2-kb deletion Corfù type (HBD g.-5946_1262del), Hb A2-Mitsero (g.14C>T), Hb A2-Etolia (g.385T>C), Hb A2-Coburg (g.1376G>A). Correlation between genotype and phenotype was established in 103 carriers.

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Section: Origin and Spread Of The Allelesmentioning

confidence: 92%

Section: Origin and Spread Of The Allelesmentioning

confidence: 99%

Epidemiology of the delta globin alleles in southern Italy shows complex molecular, genetic, and phenotypic features

Angioletti

Lacerra

Gaudiano³

et al. 2002

Hum. Mutat.

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“…, 2002). It occurs in circa 1.6% of African‐Americans (Vella, 1977). Prevalence figures are not available for Afro‐Caribbeans in the UK.…”

Section: Introductionmentioning

confidence: 99%

Haemoglobin A₂′ and its significance in β thalassaemia diagnosis

Abdelgadir

Phelan

Bain

2009

Int J Lab Hematology

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We have studied, haemoglobin A(2)' (A(2) prime), a delta chain variant haemoglobin occurring in a small percentage of individuals of African ancestry. In heterozygotes, the percentage of haemoglobin A(2)' was found to be slightly lower then the percentage of haemoglobin A(2), suggesting that the variant delta chain is synthesized at a reduced rate. When quantifying haemoglobin A(2) for the diagnosis of beta thalassaemia heterozygosity, it is essential to add together the A(2) and A(2)' to give 'total haemoglobin A(2)'. However, it not necessary to use a different reference range for total haemoglobin A(2) in A(2)' heterozygotes. When using microcolumn chromatography, A(2)' was found to be measured with A(2). On the high-performance liquid chromatography instrument studied, haemoglobin A(2)' fell in the haemoglobin S window but its retention time differed from that of haemoglobin S.

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“…Hemoglobin (Hb) A2' (also called HbB2) is the most common delta-globin chain defect and is reported to occur in 1-2% of the African American population [1][2][3][4][5][6][7][8]. Hemoglobin A2' may be present in homozygous and heterozygous states, as well as in combination with thalassemias [9][10][11]. The major clinical significance of HbA2' is that failure to detect it might lead to an underestimation of the total HbA2, leading to failure to diagnose β-thalassemia minor.…”

Section: Introductionmentioning

confidence: 99%

Higher Sensitivity of Capillary Electrophoresis in Detecting Hemoglobin A2'

et al. 2012

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HbA2' (also called Hb B2) is the most common delta-globin chain defect and is reported to occur in 1-2% of the African American population. The major clinical significance of HbA2' is that the failure to detect it might lead to an underestimation of the total HbA2, leading to failure to diagnose β-thalassemia minor. In order to diagnose β-thalassemia minor, both HbA2 and HbA2' levels must be combined.Hb A2' accounts for a small percentage (1-2%) of the total hemoglobin in heterozygotes. It is difficult to detect this small amount by traditional gel electrophoresis. Using HPLC Hb A2' is easily detected as it produces a minor peak in the S window. Other conditions which might interfere with detection of HbA2' by HPLC include Hb S trait or Hb SS disease (Hb A2' hidden in the S peak), transfused Hb SS (Hb S peak may be very small), Hb C trait or Hb CC disease (glycosylated Hb C elutes in the S window), and Hb G (Hb G2 elutes in the S window). All of the above conditions, including Hb A2', occur most commonly in the same ethnic group (African American). We reviewed 654 consecutive cases over a period of three months for the presence of Hb A2' in our laboratory where capillary electrophoresis is used as the primary diagnostic tool. We detected seven cases (1.07 %) of HbA2'. In contrast, we did not detect any HbA2' using conventional gel electrophoresis in the last one year (2,580 cases). Although in none of the seven cases the sum of Hb A2 and Hb A2' exceeded 3.5%, we believe that capillary electrophoresis allows for a better detection of Hb A2' than gel electrophoresis and HPLC.

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Variation in Hemoglobin A₂

Cited by 17 publications

References 103 publications

Epidemiology of the delta globin alleles in southern Italy shows complex molecular, genetic, and phenotypic features

Epidemiology of the delta globin alleles in southern Italy shows complex molecular, genetic, and phenotypic features

Haemoglobin A₂′ and its significance in β thalassaemia diagnosis

Higher Sensitivity of Capillary Electrophoresis in Detecting Hemoglobin A2'

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Variation in Hemoglobin A2

Cited by 17 publications

References 103 publications

Epidemiology of the delta globin alleles in southern Italy shows complex molecular, genetic, and phenotypic features

Epidemiology of the delta globin alleles in southern Italy shows complex molecular, genetic, and phenotypic features

Haemoglobin A2′ and its significance in β thalassaemia diagnosis

Higher Sensitivity of Capillary Electrophoresis in Detecting Hemoglobin A2'

Contact Info

Product

Resources

About

Variation in Hemoglobin A₂

Haemoglobin A₂′ and its significance in β thalassaemia diagnosis