Two yeast artificial chromosomes of the HLA class I region were subcloned. Four of the subclones studied displayed restriction polymorphisms that corresponded to six bi-allelic series. Allelic distribution of the anonymous markers was then studied by comparing a control population with a group of patients with familial haemochromatosis. Only one marker presents an unequivocal association with the haemochromatosis gene and is 100 kb centromeric to HLA-A. This association however is not as strong as with HLA-A3. The results suggest two possible locations for the haemochromatosis gene: less than 100 kb centromeric to the HLA-A locus, or on the telomeric side.