HLA-A74

HLA-A74 (A74) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α⁷⁴ subset of HLA-A α-chains. For A74, the alpha "A" chain are encoded by the HLA-A*74 allele group and the β-chain are encoded by B2M locus. A74 and A*74 are almost synonymous in meaning. A74 is a split antigen of the broad antigen serotype A19. A74 is a sister serotype of A29, A30, A31, A32, and A33.

HLA-A74
(MHC Class I, A cell surface antigen)
HLA-A74
About
Protein	transmembrane receptor/ligand
Structure	αβ heterodimer
Subunits	HLA-A*74--, β2-microglobulin
Subtypes
Subtype allele Available structures A74 *7401 {{{cNick2}}} *74{{{cAllele2}}} {{{cNick3}}} *74{{{cAllele3}}} {{{cNick4}}} *74{{{cAllele4}}}
Rare alleles
Subtype allele Available structures A74.3 *7403 {{{rnick2}}} *74{{{rallele2}}} {{{rnick3}}} *74{{{rallele3}}}
Alleles link-out to IMGT/HLA database at EBI

Further information: History and naming of human leukocyte antigens

A74 is more common in Subsaharan Africa. A74 is a rare HLA-A allele group.

Serotype

A74 recognition of some HLA A*74 gene products

A*74	A74	A19	Sample
allele	%	%	size (N)
*7401	40	11	119
*7403	17	0	29

A74 has a poor serotyping rate.

Disease associations

A significant association has been found between A74 and nasal polyposis.

Allele distribution

HLA A*7401 frequencies

Study population	Freq.  (in %)
Colombia African Black	11.6
Kenya	9.4
Cameroon Beti	8.3
Guinea Bissau	7.7
Kenya Luo	7.2
Burkina Faso Mossi	6.6
South African Natal Zulu	6.5
Cape Verde Southeastern I…	5.6
Uganda Kampala	5.2
Cameroon Yaounde	5.0
Cameroon Bamileke	4.5
USA African America	4.0
Cameroon Sawa	3.8
South Africa Tswana	3.7
Mali Bandiagara	3.6
Iran Baloch	2.8
Zimbabwe Harare Shona	2.7
Zambia Lusaka	2.3
Senegal Niokholo Mandenka	2.2
Burkina Faso Rimaibe	2.1
Tunisia Ghannouch	1.8
Kenya Nandi	1.7
Brazil Parana Mulatto	1.6
Brazil	1.5
Morocco Nador Metalsa Cla…	1.4
Thailand Northeast	1.2
Venezuela Colonia Tovar	1.2
Brazil Belo Horizonte	1.1
Thailand	1.1
Tunisia Tunis	1.1
Turkey (1)	1.1
Allele frequencies presented, only

HLA A*7403 frequencies

Study population	Freq.  (in %)
Kenya Luo	2.8
Argentina Toba Rosario	0.6
Iran Baloch	0.6
Saudi Arabia Guraiat and …	0.5
Kenya	0.3
Madeira	0.3
Uganda Kampala	0.3
Allele frequencies presented, only

Sources

• Madrigal JA, Belich MP, Hildebrand WH, et al. (November 1992). "Distinctive HLA-A,B antigens of black populations formed by interallelic conversion" (PDF). J. Immunol. 149 (10): 3411–5. PMID 1431115.