HLA-A2 (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 haplotypes.

Further information: HLA serotypes explained

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 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.

Read more about HLA-A2:  Serotype, Alleles, A2-B Haplotypes

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... 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). ...