title: HLA-A25
text: # HLA-A25
  
  HLA-A25 (A25) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of $α^{25}$ subset of HLA-A α-chains. For A25, the alpha "A" chain are encoded by the HLA-A*25 allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*2501. A25 and A*25 are almost synonymous in meaning. A25 is a split antigen of the broad antigen serotype A10. A25 is a sister serotype of A26, A34, A43, and A66.
  
  A25 is more common in SW Asia to NW Europe. A25 is believed to have been formed by a single gene conversion between another HLA-A and the A*2601 allele..
  
  ## Serotype
  
  A25 recognition of some HLA A*25 gene products :
  
  | A*25 | A25 | A10 | Sample |
  | - | - | - | - |
  | allele | % | % | size (N) |
  | *2501 | 95 | 2 | 1375 |
  
  A25 reasonably good serotyping with no overt false recognition..
  
  ## A25 frequencies
  
  A*2501 distribution is primarily located in Western Eurasia. Frequency tends to be highest in the populations that underwent later neolithization suggesting A*2501 spread in Europe. The high frequency in Saudi Arabia is suggestive of a source.
  
  