THE FREQUENCY OF THE HEMOCHROMATOSIS-ASSOCIATED GENOTYPE D6S265-1-D6S105-8 IN BLOOD-DONORS

Homozygosity for HLA-A3 and the microsatellite markers D6S265 allele 1 and D6S105 allele 8 is associated with a high relative risk for genet ic haemochromatosis - indeed we and others have suggested that a haplo type including D6S265-1, HLA-A3 and D6S105-8 is specific for haemochro matosis. To determine the frequency of this haplotype and examine its specificity for haemochromatosis we have analysed data from 7820 blood donors from South Wales. The frequency of homozygosity for D6S265-1, HLA-A3 and D6S105-8 was 1 in 280. Calculations based on the prevalence of haemochromatosis suggest that about 50% of chromosomes carrying D6 S265-1:HLA-A3:D6S105-8 also carry the haemachromatosis gene. This info rmation is of value for assessing the risk that the partner of a patie nt with haemochromatosis also carries the haemochromatosis gene.