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Hemoglobin, alpha 2

From Wikipedia, the free encyclopedia
HBA2
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesHBA2, HBA-T2, HBH, Hemoglobin, alpha 2, hemoglobin subunit alpha 2, ECYT7
External IDsOMIM: 141850; MGI: 96015; HomoloGene: 469; GeneCards: HBA2; OMA:HBA2 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000517

NM_008218

RefSeq (protein)

NP_000508
NP_000508.1
NP_000549.1

NP_001077424

Location (UCSC)Chr 16: 0.17 – 0.17 MbChr 11: 32.23 – 32.23 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Hemoglobin, alpha 2[5] also known as HBA2 is a gene that in humans codes for the alpha globin chain of hemoglobin.[6][7]

Function

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The human alpha globin gene cluster is located on chromosome 16 and spans about 30 kb, including seven alpha like globin genes and pseudogenes: 5'- HBZ - HBZP1 - HBM - HBAP1 - HBA2 - HBA1 - HBQ1 -3'. The HBA2 (α2) and HBA11) coding sequences are identical. These genes differ slightly over the 5' untranslated regions and the introns, but they differ significantly over the 3' untranslated regions.

Protein

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Two alpha chains plus two beta chains constitute HbA, which in normal adult life accounts for about 97% of the total hemoglobin; alpha chains combine with delta chains to constitute HbA-2, which with HbF (fetal hemoglobin), composed of alpha and gamma chains, make up the remaining 3% of adult hemoglobin.

Clinical significance

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Alpha-thalassemias most commonly result from deletions of any of the four alpha alleles, although some alpha thalassemias have been reported that are due to mutations other than deletion. Deletion of 1 or 2 alleles is clinically silent. Deletion of 3 alleles causes HbH disease, resulting in anemia and hepatosplenomegaly. Deletion of all 4 alleles is lethal because it renders the body unable to make fetal hemoglobin (HbF), adult hemoglobin (HbA) or adult variant hemoglobin (HbA2), and results in hydrops fetalis.[8]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000188536Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000069919Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ "HBA2 gene: MedlinePlus Genetics".
  6. ^ Liebhaber SA, Goossens MJ, Kan YW (Dec 1980). "Cloning and complete nucleotide sequence of human 5'-alpha-globin gene". Proceedings of the National Academy of Sciences of the United States of America. 77 (12): 7054–8. Bibcode:1980PNAS...77.7054L. doi:10.1073/pnas.77.12.7054. PMC 350439. PMID 6452630.
  7. ^ Higgs DR, Vickers MA, Wilkie AO, Pretorius IM, Jarman AP, Weatherall DJ (Apr 1989). "A review of the molecular genetics of the human alpha-globin gene cluster". Blood. 73 (5): 1081–104. doi:10.1182/blood.V73.5.1081.1081. PMID 2649166.
  8. ^ "Entrez Gene: HBA2 hemoglobin, alpha 2".

Further reading

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This article incorporates text from the United States National Library of Medicine, which is in the public domain.