A study of genetic markers was undertaken in a kindred containing 19 individuals affected with a depressive illness. The pedigree was selected for study because the distribution of affected family members is consistent with transmission of an autosomal gene for susceptibility to psychiatric abnormality. Evidence against linkage of the postulated dominantly transmitted susceptibility gene with 29 segregating marker loci, including HLA, excluded the postulated gene from 6% of the autosomal genome. However, the distribution of HLA haplotypes in affected sibling pairs and within the family as a whole is compatible with the hypothesis that expression of affective disorder in this family depends in part on an HLA-linked susceptibility gene.