Objective: We reported an association between juvenile dermatomyositis (JDMS) and the HLA-DQA1*0501 allele. The purpose of this study was to determine whether there is evidence for linkage between JDMS and the DQA1*0501 allele in JDMS families.
Methods: The study population included 18 unrelated patients with JDMS, their parents, and 49 unaffected siblings. Using molecular genetic techniques, we studied the HLA genes, DRB1, DQA1, and tumor necrosis factor-alpha.
Results: Using the transmission disequilibrium test, we confirmed our earlier observations that the HLA-DQA1*0501 allele confers primary susceptibility to JDMS.
Conclusion: DQA1*0501 confers genetic risk for JDMS; we cannot exclude the effects of alleles at other linked loci that were not studied or interactive effects between DQA1 alleles and alleles at other loci.