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major histocompatibility complex (human), class I, A1
Alleles A*0101
Structure (See HLA-A)
*0101 *0102 *0103
Symbol(s) HLA-A1
EBI-HLA A*0101
EBI-HLA A*0102
EBI-HLA A*0103
Shared data
Locus chr.6 6p21.31

HLA-A1 (A1) is an HLA-A serotype. The serotype identifies the more common HLA-A*01 gene products. A1 is more common in Europe than elsewhere, it is part of a long haplotype that appears to have been frequent in the ancient peoples of Northwestern Europe. Part of this haplotype is A1-Cw7-B8 (its serotype name), which has a frequency mode in Ireland where it is the highest frequency A-Cw-B type in Europe.


A1 serotype recognition of Some HLA A*01 allele-group gene products[1]
A*01 A1 Sample
allele % % size (N)
0101 99% 5612
0102 95 129
0103 78 9

The serotyping capability of the A1 serotype is excellent. For the A1 group there are 24 alleles, 7 nulls, 14 protein variants. Two alleles, A*0101 and A*0102, comprise the overwhelming majority of alleles.

Disease Associations

By allele

A*0101 appears to alter risk for type 1 diabetes.[2] Because A*0101 is linked to DR3-DQ2.5 (see below), and because this class II haplotype has a bearing on diabetes risk (2nd most potent risk factor) some of this risk could be due to linkage with DR3.

By haplotype

A1-B58 (A1-B17 where B58 is dominant) is associated with antineutrophil cytoplasmic antibodies (ANCA)[3]

A-B Haplotypes

HLA A1-B8 haplotype frequencies
[4] Ireland 14.4 1
[5] Northern Ireland 11.5 1 1
[6] Swedish 11.5 1
[7] Dutch Netherlands 9.8
[6] Yugoslavian 9.7 1
[6] British 9.7 1
[6] Hungarian 9.4 1
[8] CEPH France 8.5 1 1
[6] Czech 7.8 1
[9] Swiss 6.7 3
[6] Austria 4.5 2
[6] Italy 4.2 1
[6] Basque 4.2
[6] Polish 4.0
[10] Uganda 3.7 1
[6] Spanish 2.8 4
[1] Romania 2.8
[6] Greek 2.3
[6] Luo Kenya 1.7 2
[6] Nandi Kenya 1.4 2
[11] Oman Arabia 1.4
[6] Japanese 0.1
1Cw*0701 (Eur.), ²Cw*0704 (Afr.)
  • A1-B7 Armenia, Austria, NW Europe (regional recombinant between A1-B8 and A2/A3-B7)
  • A1-B13 Uralic
  • A1-B35 (Albania, Belgium, Italy, Greece, France - Eastern mediterranian in origin)
  • A1-B37 Yakuts, Tribal-India, Iyers-India, Mongolian, Indian, Orochon, Romanian, Yugoslavia, Korean, Albania, French, German, Manchu
  • A1-B51 Yugoslavia, Germany, Iberia, Italy
  • A1-B52 Bharghavas-India, Tribal-India, Italy, Iberia, France
  • A1-B57 (See tables on discussion page)
  • A1-B58 (See tables on discussion page)


A1-Cw7-B8 is the multi-serotype designation for the haplotype HLA-A*0101:C*0701:B*0801, the class I portion, of the "Super B8 Haplotype" ancetral "Ancestral Haplotype" (A1-B8-DR17(3)-DQ2.5). The full haplotype is (for relative distances see Human leukocyte antigens:

A*0101 : C*0701 : B*0801 : DRB1*0301 : DQA1*0501 : DQB1*0201

The frequency node for this haplotype is in Western Ireland. Where as the most allelic diversity (variations of A*01 or B*08 are within East Africa. The Cw7 locus carries several variants Europe (Cw*0701) Africa (Cw*0701 & Cw*0704) It suprisingling maintains DR linkage, over 2 million nt distance is still shows relative linkage disequilibrium with DR3. In NW Europe linked to DRB1*0301 and in SE Europe DRB1*0301/*0302. It is also disequilibrated in its linkage to DQ2, and in NW Europe it is linked to DQA1*0501:DQB1*0201. Because of the incredible linkage disequilibrium this haplotype is believed to have been under positive selection in Europe's prehistoric period. When DR or DQ typing is not present for a population this haplotype can substitute as a marker for DQ2.5 abundance and coeliac disease risk, as in the case for Ireland.

The rightmost column in the table on the right shows the rank of A1-B8 in A-B haplotypes, it is the most common top ranked haplotype in Western Europe, in fact it is one of the more common A-B haplotypes in the world.


  1. derived from IMGT/HLA
  2. Noble J, Valdes A, Bugawan T, Apple R, Thomson G, Erlich H (2002). "The HLA class I A locus affects susceptibility to type 1 diabetes". Hum Immunol. 63 (8): 657–64. PMID 12121673.
  3. Shankarkumar U, Ghosh K, Pradhan V, Badakere S, Mohanty D (2005). "Immunogenetic association in patients with antineutrophil cytoplasmic antibodies (ANCA) from Mumbai, Maharashtra, India". J Autoimmun. 24 (3): 227–33. PMID 15848045.
  4. 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.
  5. 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.
  6. 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 6.11 6.12 6.13 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.
  7. 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.
  8. Bugawan T, Klitz W, Blair A, Erlich H (2000). "High-resolution HLA class I typing in the CEPH families: analysis of linkage disequilibrium among HLA loci". Tissue Antigens. 56 (5): 392–404. PMID 11144287.
  9. 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.
  10. Cao K, Moormann A, Lyke K, Masaberg C, Sumba O, Doumbo O, Koech D, Lancaster A, Nelson M, Meyer D, Single R, Hartzman R, Plowe C, Kazura J, Mann D, Sztein M, Thomson G, Fernández-Viña M (2004). "Differentiation between African populations is evidenced by the diversity of alleles and haplotypes of HLA class I loci". Tissue Antigens. 63 (4): 293–325. PMID 15009803.
  11. Williams F, Meenagh A, Darke C, Acosta A, Daar A, Gorodezky C, Hammond M, Nascimento E, Middleton D (2001). "Analysis of the distribution of HLA-B alleles in populations from five continents". Hum Immunol. 62 (6): 645–50. PMID 11390040.

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