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:
GGGTAAGGTCGGCGCGCACGCTGGC [G/A] AGTATGGTGCGGAGGCCCTGGAGAG (Strand: +)

Protein sequence:
MVLSPADKTNVKAAWGKVGAHAGKYGAEALERMFLSFPTTKTYFPHFDLSHGSAQVKGHGKKVADALTNAVAHVDDMPNALSALSDLHAHKLRVDPVNFKLLSHCLLVTLAAHLPAEFTPAVHASLDKFLASVSTVLTSKYR

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.

External Links

HbVar	dbSNP
OMIM	SwissVar
ClinVar

Phenotype

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

IthaPhen

Heterozygous records (preview in IthaPhen)

Location

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

HPLC

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ID	Hb Variant	Gene	Instrument	Method	Area (%)	Ret Time (min)	Comments
93	Hb Chad	α2	D-10	Dual Kit Program	22.5	4.49	Heterozygous. Clinically normal.	[PDF]
94	Hb Chad	α2	VARIANT	β-thal Short Program	25.2	4.89	Heterozygous. Clinically normal.	[PDF]
95	Hb Chad	α2	VARIANT II	β-thal Short Program	23.6	4.96	Heterozygous. Clinically normal.	[PDF]
96	Hb Chad	α2	VARIANT II	Dual Kit Program	20.6	4.115	Heterozygous. Clinically normal.	[PDF]

Sequence Viewer

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Publications / Origin

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
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
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
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)

A/A	Date	Curator(s)	Comments
1	2010-06-16 16:13:15	The IthaGenes Curation Team	Created
2	2014-03-13 09:37:28	The IthaGenes Curation Team	Reviewed.
3	2017-04-10 14:33:55	The IthaGenes Curation Team	Reviewed. Mutation Names/DNA Info added.
4	2022-04-08 10:36:46	The IthaGenes Curation Team	Reviewed. Affected gene corrected.
5	2022-04-08 10:49:52	The IthaGenes Curation Team	Reviewed. Comment added.

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