Here is a map showing the allele frequency of HLA-DR3. The maximum frequencies are observed in Sardinia (56%), the Basque country (19.5%), Ireland (18%), Morocco (16.5%), Tunisia (16.5%), Libya (15.5%), Saudi Arabia (15.5%), Belgium (15.5%), Wales (15%), Algeria (15%), England/Scotland (14.5%), Sweden (13.5%), Norway (13%), as well as southern/central Spain (13%). You can also visualise the data on this table of HLA-DR frequencies.



In Europe and North Africa, the distribution of DR3 resembles that of mtDNA haplogroups H1 and H3, which also have high frequencies in Sardinia, the Basque country, Wales, Ireland, Scandinavia and the Maghreb. These haplogroups are thought to be descended from Mesolithic Iberians and/or Northwest Africans and could have spread to western France, Britain, Ireland, the Low Countries and Scandinavia with the expansion of the Megalithic culture and the Bell Beaker trading network.

Interestingly in all these regions people are highly dolicocephalic (long headed).


Medical associations

HLA-DR3 is associated with early-age onset myasthenia gravis, Hashimoto's thyroiditis (along with DR5), primary sclerosing cholangitis, and opportunistic infections in AIDS, but lowered risk for cancers.

DR3-DQ2 linkage is associated with coeliac disease, dermatitis herpetiformis, Diabetes mellitus type 1.


SNP's

You can verify if you carry HLA-DR3 by checking your raw data from 23andMe, Geno 2.0 or FamilyFinder. There are several subclades (3:01 to 3:09) but 99% of Europeans belong to 3:01.

- DRB1*03:01 : rs2040410 (A means DR3)