HLA-DQ7

HLA-DQ7 (DQ7) is an HLA-DQ serotype that recognizes the common HLA DQB1*0301 and the less common HLA DQB1*0304 gene products. DQ7 is a form of 'split antigen' of the broad antigen group DQ3 which also contains DQ8 and DQ9.

DQ7 is linked by haplotype to a number of DQA1 (DQ alpha chain) genes, producing in cis-haplotype form, a large number of DQ αβ isoforms. These DQ alpha chains are also known to form transhaplotype isomers with other HLA-DQ.

DQ7 is linked to the following alpha chains genes (DQA1*)

Serotyping efficiency. The serotyping efficiency of DQ7 toward DQB1*0301 is reasonably good, but still results in some false negatives, for *0304 the typing efficiency is poor and cross-reaction with DQ8 is relatively high.

DQB1*0301 is the major DQ7 allele DQB1*0301 appears to be associated with lupus anticoagulant.

DQB1*0304 is the minor DQ7 allele

DQ haplotypes of this serotype are formed between the cis-chromosomal genes of the DQA1 locus. This includes DQA1*0301, *0302, *0303, *0401, *0505, *0601.

There is a rather large degree of disequilibration about DQA1*0301 suggesting that this is one of the older and more established HLA DQB1* alleles in Eurasia. The intron structure of DQB1 suggest that DQB1*0301 DQB1*0302/*0303 split occurred before DQB1*0302/*0303, the distribution of *03 in Africa suggest that recombination DQA1*03:DQB1*0301 are primarily the result of recombination events that have occurred in Africa. A recent study of myasthenia gravis in Houston confirms the presence of A*0505:B*0301 in Nigeria. B1*0301 and A1*03 haplotypes are found at relatively high frequencies in SE Asia and Austronesia, also indicating that it is well established in the exo-African population.