IthaID: 485

Names and Sequences

Functionality: Globin gene causative mutation Pathogenicity: N/A
Common Name: CD 23 GAG>AAG [Glu>Lys] HGVS Name: HBA2:c.70G>A
Hb Name: Hb Chad Protein Info: α2 23(B4) Glu>Lys

Context nucleotide sequence:

Protein sequence:

Also known as: Hb E-Keelung

Comments: Hb Chad presented increased oxygen affinity 20% in a Japanese male [PMID:6689417]. The missense mutation GAG>AAG [Glu>Lys] at codon 23, also found in the context of a −α3.7 thalassaemia chromosome [IthaID:3915]. A recent report [PMID:35059272] reveals that the G>A substitution is located on codon 23 of the ΗΒΑ2.

We follow the HGVS sequence variant nomenclature and IUPAC standards.


Hemoglobinopathy Group: Structural Haemoglobinopathy
Hemoglobinopathy Subgroup: α-chain variant
Allele Phenotype:N/A
Stability: N/A
Oxygen Affinity: N/A
Associated Phenotypes: N/A


Chromosome: 16
Locus: NG_000006.1
Locus Location: 33845
Size: 1 bp
Located at: α2
Specific Location: Exon 1

Other details

Type of Mutation: Point-Mutation(Substitution)
Effect on Gene/Protein Function: Missense codons (Protein Structure)
Ethnic Origin: African, Chinese, Japanese
Molecular mechanism: N/A
Inheritance: Recessive
DNA Sequence Determined: Yes


Disclaimer: The HPLC images are provided as an information resource only. Bio-Rad Laboratories, Inc and the ITHANET Portal disclaim responsibility and have no liability if this information is used for diagnostic or treatment purposes. D-10™ and VARIANT™ are registered trademarks of Bio-Rad Laboratories, Inc. and used with permission. Redistribution and use of the above material is allowed only with permission by Bio-Rad Laboratories, Inc. To access HPLC images and reports for different variants, use the IthaChrom tool.
ID Hb Variant Gene Instrument Method Area (%) Ret Time (min) Comments
93Hb Chadα2D-10Dual Kit Program22.54.49Heterozygous. Clinically normal.[PDF]
94Hb Chadα2VARIANTβ-thal Short Program25.24.89Heterozygous. Clinically normal.[PDF]
95Hb Chadα2VARIANT IIβ-thal Short Program23.64.96Heterozygous. Clinically normal. [PDF]
96Hb Chadα2VARIANT IIDual Kit Program20.64.115Heterozygous. Clinically normal.[PDF]

In silico pathogenicity prediction

Sequence Viewer

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Publications / Origin

  1. Boyer SH, Crosby EF, Fuller GF, Ulenurm L, Buck AA, A survey of hemoglobins in the Republic of Chad and characterization of hemoglobin Chad:alpha-2-23Glu--Lys-beta-2., Am. J. Hum. Genet. , 20(6), 570-8, 1968 PubMed
  2. Blackwell RQ, Weng MI, Huang JT, Haemoglobin Chad, alpha23 GLU leads to LYS, in a Chinese family in Taiwan., Trop Geogr Med , 25(4), 393-6, 1973 PubMed
  3. Harano T, Harano K, Shibata S, Ueda S, Mori H, Imai K, Yoshida T, Hemoglobin Chad [alpha 23 (B4) Glu replaced by Lys] discovered in a Japanese with questionable polycythemia., Hemoglobin, 7(6), 581-4, 1983 PubMed
  4. Yoshino K, Hirota Y, Ogawa W, Sugawara K, Kawaguchi A, Yoshino H, Ishibashi M, Yoshino G, Koga M, A case of α-chain variant hemoglobin (Hb Chad) with falsely high HbA1c levels measured by immunoassay., Diabetol Int, 13(1), 330-335, 2022 PubMed
Created on 2010-06-16 16:13:15, Last reviewed on 2022-04-08 10:49:52 (Show full history)

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