ABSOLUTE LINKAGE OF CELIAC-DISEASE AND DERMATITIS-HERPETIFORMIS TO HLA-DQ

This report shows the absolute genetic linkage of celiac disease (CD) to the HLA-DQ region, and supports the fact that dermatitis herpetifor mis (DH) follows the same pattern of HLA-mediated susceptibility in ex tensive series of Caucasian Spanish patients. Ninety-five percent of C D (201 of 212) and 100% of DH (55) patients could produce DQ alpha 10 501-DQ beta 102 heterodimers. Negative CD patients for this combinati on were mostly DR4-DQ8 (DQA103-DQB1*0302) (9 of 11), along with a res tricted number of complementary chromosomes. Comparison of observed an d expected DQA1-DQB1 genotype distributions (Hardy-Weinberg equilibriu m) showed that the excess of patients with DQB102 in double doses wou ld be the consequence for which this allele should be complemented by DQA10501. Homozygosity for DQA1*0501 would restrain susceptibility to CD and DH.