Two groups totaling 67 patients with idiopathic focal, segmental, and generalized dystonia, including torticollis, were compared with normal controls to determine whether there was a difference in the frequency of A, B, and C locus human leukocyte (HLA) antigens. The results indicated no statistically significant deviations in HLA antigen frequencies between the patients and the normal controls. Thirteen of the patients with idiopathic torsion dystonia were compared with normal controls for DR locus antigens. A trend of increased DR3 antigens observed in the patients may be significant. HLA genotyping of parents and children in nine families was also studied to determine if an HLA-linked factor could be related to the dystonic syndrome in the children. The results were indeterminate, suggesting that further family studies are required to resolve this issue.