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major histocompatibility complex (human), class I, A3
Alleles A*0301
Structure (See HLA-A)
*0301 *0302
Symbol(s) HLA-A3
EBI-HLA A*0301
EBI-HLA A*0302
Shared data
Locus chr.6 6p21.31

HLA-A3 (A3) is an HLA-A serotype. The serotype identifies the more common HLA-A*03 gene products. A3 is more common in Northwestern and Central Europe, Central Asia, India and Arabia. It is less common on the West Pacific Rim, Africa or indigenous populations of the New World.


A3 serotype recognition of Some HLA A*03 allele-group gene products[1]
A*03 A3 Sample
allele % % size (N)
*0301 99 3504
*0302 78 342
*0305 20 5

A3 is primarily composed of A*0301 and *0302 which serotype well with anti-A3 antibodies. There are 26 non-synonymous variants of A*03, 4 nulls, and 22 protein variants.

Disease Associations

By serotype

A3 serotype is a secondary risk factor for myasthenia gravis,[2] lower CD8+ levels in hemochromatosis patients[3][4]

By allele

A*0301 modulates increased risk for Multiple Sclerosis[5]

A3-B Haplotypes

HLA A3-B7 haplotype frequencies
freq Rank in
ref. Population (%) Pop.
[6] Swiss 9.1 1
[7] Ireland 8.6
[8] Austria 7.4 1
[9] Northern Ireland 6.5 1
[10] Netherlands 6.6
German 5.7
Svans 2.7
Tuscan Italy 2.7
Bulgaria 1.1
1 Cw*0702 (Europe)

A3-B8 (Romania, svanS)
A3-B35 (Bulgaria, Croatia, E. Black Sea)
A3-B55 (E. Black Sea)


A3-B7 is bimodal in frequency in Europe with one node in Ireland and the other in Switzerland, relatively speaking Switzerland appears to be higher. A3-Cw7-B7 is one of the most common multigene haplotypes in the western world, particularly in Central and Eastern Europe.

A*0301 : C*0702 : B*0702 : DRB1*1501 : DQA1*0102 : DQB1*0602


  1. derived from IMGT/HLA
  2. Machens A, Löliger C, Pichlmeier U, Emskötter T, Busch C, Izbicki J (1999). "Correlation of thymic pathology with HLA in myasthenia gravis". Clin Immunol. 91 (3): 296–301. PMID 10370374.
  3. Barton J, Wiener H, Acton R, Go R. "HLA haplotype A*03-B*07 in hemochromatosis probands with HFE C282Y homozygosity: frequency disparity in men and women and lack of association with severity of iron overload". Blood Cells Mol Dis. 34 (1): 38–47. PMID 15607698.
  4. Cruz E, Vieira J, Almeida S, Lacerda R, Gartner A, Cardoso C, Alves H, Porto G. "A study of 82 extended HLA haplotypes in HFE-C282Y homozygous hemochromatosis subjects: relationship to the genetic control of CD8+ T-lymphocyte numbers and severity of iron overload". BMC Med Genet. 7: 16. PMID 16509978.
  5. Fogdell-Hahn A, Ligers A, Grønning M, Hillert J, Olerup O (2000). "Multiple sclerosis: a modifying influence of HLA class I genes in an HLA class II associated autoimmune disease". Tissue Antigens. 55 (2): 140–8. PMID 10746785.
  6. 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.
  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.
  8. 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.
  9. 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.
  10. 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.

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