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.
[5] DQ7.3 appears to be associated with oral ulcerations and gingival disease [6] DQA1*0401:DQB1*0301 (DQ7.4) This haplotype is found in Siberia, Africa but also at low levels in Western Europe.
DQA1*0505:DQB1*0301 (DQ7.5) was gene-typed as DQA1*0501:DQB1*0301 until it was recognized that there was amino acid sequence variant in the preprocessed DQA1* gene product (proto-α-chain polypeptide encoded DQA1*0505).
[9] Cereals were first domesticated in the Near and Middle East more than 10,000 years ago and selection may explain DQ7.5's higher frequencies.
(See: Triticeae) The processed alpha subunit of DQA1*0505 is identical to that of DQA1*0501, but some slight differences in the association with autoimmune disease are observed, possibly as a result of linked DR and DQB1 genes.
DQB1*0301 may be under current positive selection in the human population, at least in areas where DQ2.5 and DQ8 are high, as it confers resistance to type 1 diabetes.
[11] DQA1*0505, DQB1*0301 appear to increase the risk for melanoma in the Spanish population however this may have a linkage to more recent fair skinned migrants.
DQB1*0301 is also associated with allergic fungal sinusitis, human papillomavirus (HPV) induced warts, limited cutaneous systemic sclerosis in Africans, and primary sclerosing cholangitis in Southern Europeans.