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HLA-A2




major histocompatibility complex (human), class I, A2
Alleles	A0201 A0202 A0203 A0205 A0206 A0207 A*0211
Structure (See HLA-A)
Identifiers	0201 0202 0203 0205 0206 0207 *0211
Symbol(s)	HLA-A2
EBI-HLA	A*0201
EBI-HLA	A*0202
EBI-HLA	A*0203
EBI-HLA	A*0205
EBI-HLA	A*0206
EBI-HLA	A*0207
EBI-HLA	A*0211
Shared data
Locus	chr.6 6p21.31

HLA-A2 (A2) is an HLA-A serotype. The serotype identifies the gene products of many HLA-A*02 alleles, including HLA-A*0201, *0202, *0203, *0206, and *0207 gene products. A*02 is globally common, but A*0201 is at high frequencies in Northern Asia and North America. A2 is the most diverse serotye, showing diversity in Eastern Africa and Southwest Asia. While the frequency of A*0201 in Northern Asia is high, its diversity is limited to A*0201 the less common Asian variants A*0203, A*0206.

Additional recommended knowledge

Essential Laboratory Skills Guide

Weighing the right way

Daily Sensitivity Test

1 Serotype
2 Disease Associations
- 2.1 By serotype
- 2.2 By haplotype
3 A2-B Haplotypes
- 3.1 A2-Cw5-B44
4 References

Serotype

A2 serotype recognition of Some HLA A*02 allele-group gene products^[1]
A*02	A2		Sample
allele	%	%	size (N)
*0201	98		6315
*0202	81		859
*0203	64		472
*0204	78		28
*0205	81		462
*0206	68		636
*0207	80		135
*0211	74		228

The serotyping for the most abundant A*02 alleles is good. For A*0203, A*0206, A*0207 serotyping is borderline useful. There is a separate serotyping for A203 and A210. There are over 125 alleles identified (mostly by sequence homology) as being A2, of those 8 are nulls, and a large majority have unknown serotypes.

Disease Associations

By serotype

A2 Associated with spontaneous abortion in A2+/A[other] phenotypic children^[2]

By haplotype

A*02:Cw*16 is associated with increased higher viral load in HIV^[3]

A2-B Haplotypes

A2-B7 (Node in Netherlands) A2-B5

A2-B51
A2-B52

A2-B8
A2-B13
A2-B14

A2-B64
A2-B65

A2-B15

A2-B62
A2-B63
A2-B70,71,75,76
A2-B46 (Node in Southern China, may be most abundant haplotype)

A2-B16

A2-B44
A2-B45

A2-B18
A2-B27
A2-B35
A2-B37 A2-B39 (Node in North American Amerinds)
A2-B40

A2-B60
A2-B61

A2-B46

A2-Cw5-B44

HLA A2-B44 haplotype frequencies
		freq		Rank in
ref.	Population	(%)		Pop.
^[4]	Cornish	11.4	¹	1
^[5]	Ireland	9.2		2
^[6]	Northern Ireland	8.0	¹	2
^[4]	Sweden	7.2		2
^[7]	Swiss	6.9		2
^[4]	Polish	6.2		1
^[4]	Spanish	5.9		1
^[4]	Ukraine	5.9		1
^[8]	Dutch Netherlands	5.9		3
^[4]	Dane	4.8		1
^[4]	Czech	4.7		3
^[4]	Basque	4.7		3
^[4]	Greek	4.5		3
^[4]	Yugoslavian	4.4
^[4]	Hungarian	3.5
^[4]	British	2.6		4
[1]	Romania	2.5
^[4]	Austria	2.4
¹Cw*0501 (Eur.)

A2-Cw5-B44 is the multi-serotype designation for the haplotype HLA-A*0201:C*0501:B*4402, the class I portion, of an ancetral haplotype (A2-B44-DR4-DQ8). The full haplotype is (for relative distances see Human leukocyte antigens:

A*0201 : C*0501 : B*4402 : DRB1*0401 : DQA1*0301 : DQB1*0302

Another haplotype that is more common in Central Europe is the (A2-B44-DR7-DQ2)

A*0201 : C*0501 : B*4402 : DRB1*0701 : DQA1*0201 : DQB1*0202

Over northwestern Europe A2-B44 shows a single common ancestor which contributed the Cw5 allele to the haplotype. The haplotype appears to have been introduced early in European prehistoric period, frequencies of the haplotype generally correlate with A1-Cw7-B8 and A2-B7. The haplotype is considerably more equilibrated relative to A1-B8 and a possible reason is gene flow from iberia or the east with related haplotypes after initial migrations.

References

^ derived from IMGT/HLA
^ Komlos L, Klein T, Korostishevsky M (2007). "HLA-A2 class I antigens in couples with recurrent spontaneous abortions". Int. J. Immunogenet. 34 (4): 241-6. doi:10.1111/j.1744-313X.2007.00682.x. PMID 17627758.
^ Tang J, Tang S, Lobashevsky E, Myracle A, Fideli U, Aldrovandi G, Allen S, Musonda R, Kaslow R (2002). "Favorable and unfavorable HLA class I alleles and haplotypes in Zambians predominantly infected with clade C human immunodeficiency virus type 1.". J Virol 76 (16): 8276-84. PMID 12134033.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Sasazuki, Takehiko; Tsuji, Kimiyoshi; Aizawa, Miki (1992). HLA 1991: proceedings of the eleventh International Histocompatibility Workshop and Conference, held in Yokohama, Japan, 6-13 November, 1991. Oxford [Oxfordshire]: Oxford University Press. ISBN 0-19-262390-7.
^ Finch T, Lawlor E, Borton M, Barnes C, McNamara S, O'Riordan J, McCann S, Darke C (1997). "Distribution of HLA-A, B and DR genes and haplotypes in the Irish population.". Exp Clin Immunogenet 14 (4): 250-63. PMID 9523161.
^ Middleton D, Williams F, Hamill M, Meenagh A (2000). "Frequency of HLA-B alleles in a Caucasoid population determined by a two-stage PCR-SSOP typing strategy.". Hum Immunol 61 (12): 1285-97. PMID 11163085.
^ Grundschober C, Sanchez-Mazas A, Excoffier L, Langaney A, Jeannet M, Tiercy J (1994). "HLA-DPB1 DNA polymorphism in the Swiss population: linkage disequilibrium with other HLA loci and population genetic affinities.". Eur J Immunogenet 21 (3): 143-57. PMID 9098428.
^ Schipper R, Schreuder G, D'Amaro J, Oudshoorn M (1996). "HLA gene and haplotype frequencies in Dutch blood donors.". Tissue Antigens 48 (5): 562-74. PMID 8988539.

v • d • e HLA-A Serotypes
HLA-A - A1 - A2 - A3 - A9 (A23 - A24) - A10 (A25 - A26 - A34 - A43 - A66) - A11 - A19 (A29 - A30 - A31 - A32 - A33 - A74) - A28 (A68 - A69) - A36 - A80

Category: HLA-A alleles

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "HLA-A2". A list of authors is available in Wikipedia.