HLA-A2
Encyclopedia
HLA-A2 is a human leukocyte antigen
serotype
within HLA-A
"A" serotype group. The serotype is determined by the antibody recognition of α2 subset of HLA-A α-chains. For A2, the alpha "A" chain are encoded by the HLA-A*02 allele group and the β-chain are encoded by B2M
locus. A2 and A*02 are almost synonymous in meaning. A2 is more common in Northern Asia and North America than elsewhere, and it is part of a several long haplotype
s.
The serotype identifies the gene product
s 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 serotype, 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.
A2-B5
A2-B8
A2-B13
A2-B14
A2-B15
A2-B16
A2-B18
A2-B27
A2-B35
A2-B37
A2-B39 (Node in North American Amerinds)
A2-B40
A2-B46
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 antigen
s:
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.
Human leukocyte antigen
The human leukocyte antigen system is the name of the major histocompatibility complex in humans. The super locus contains a large number of genes related to immune system function in humans. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and...
serotype
Serotype
Serotype or serovar refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens...
within HLA-A
HLA-A
HLA-A are a group of human leukocyte antigens that are encoded by the HLA-A locus on human chromosome 6p. The HLA genes constitute a large subset of the Major histocompatibility complex of humans. HLA-A is a component of certain MHC class I cell surface receptor isoforms that resides on the...
"A" serotype group. The serotype is determined by the antibody recognition of α2 subset of HLA-A α-chains. For A2, the alpha "A" chain are encoded by the HLA-A*02 allele group and the β-chain are encoded by B2M
B2M
B2M may refer to:*Boyz II Men, a singing group*Mitsubishi B2M, an aircraft*Back to Mine, a series of albums*Beta-2 microglobulin, a gene or protein*Business to machine, the practice of E-commerce where companies link directly to machines...
locus. A2 and A*02 are almost synonymous in meaning. A2 is more common in Northern Asia and North America than elsewhere, and it is part of a several long haplotype
Haplotype
A haplotype in genetics is a combination of alleles at adjacent locations on the chromosome that are transmitted together...
s.
The serotype identifies the gene product
Gene product
A gene product is the biochemical material, either RNA or protein, resulting from expression of a gene. A measurement of the amount of gene product is sometimes used to infer how active a gene is. Abnormal amounts of gene product can be correlated with disease-causing alleles, such as the...
s 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 serotype, 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.
Serotype
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
A2 Associated with spontaneous abortion in A2+/A[other] phenotypic childrenBy haplotype
A*02:Cw*16 is associated with increased higher viral load in HIVAlleles
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
| freq | Rank in | |||
| ref. | Population | (%) | Pop. | |
| Cornish | 11.4 | 1 | 1 | |
| Ireland | 9.2 | 2 | ||
| Northern Ireland | 8.0 | 1 | 2 | |
| Sweden | 7.2 | 2 | ||
| Swiss | 6.9 | 2 | ||
| Polish | 6.2 | 1 | ||
| Spanish | 5.9 | 1 | ||
| Ukraine | 5.9 | 1 | ||
| Dutch Netherlands | 5.9 | 3 | ||
| Dane | 4.8 | 1 | ||
| Czech | 4.7 | 3 | ||
| Basque | 4.7 | 3 | ||
| Greek | 4.5 | 3 | ||
| Yugoslavian | 4.4 | |||
| Hungarian | 3.5 | |||
| British | 2.6 | 4 | ||
| http://www.allelefrequencies.net/test/searchHaplotypePart3.asp?Population=Romanian | Romania | 2.5 | ||
| 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
HLA-DR4
HLA-DR4 is a HLA-DR serotype that recognizes the DRB1*04 gene products. The DR4 serogroup is large and has a number ofmoderate frequency alleles spread over large regions of the world.-Serology:The serological identification of DR4 is good...
-DQ8
HLA-DQ8
HLA-DQ8 is a human leukocyte antigen serotype within the HLA-DQ serotype group. DQ8 is a split antigen of the DQ3 broad antigen. DQ8 is determined by the antibody recognition of β8 and this generally detects the gene product of DQB1*0302....
). The full haplotype is (for relative distances see Human leukocyte antigen
Human leukocyte antigen
The human leukocyte antigen system is the name of the major histocompatibility complex in humans. The super locus contains a large number of genes related to immune system function in humans. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and...
s:
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.