Immunogenetic studies in families of children with juvenile dermatomyositis

Objective. We reported an association between juvenile dermatomyositis (JDMS) and the HLADQA1*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-α. 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.