The HLA system and G6PD deficiency in the Bulgarian population.

HLA typing was done on 2,956 healthy, unrelated individuals living in four areas in Bulgaria. Of these, 163 had G6PD deficiency. The persons examined lived in villages situated at different altitudes. A low degree of correlation was found only for HLA-A1, -Aw23, -Bw35 and -B40 in the selected group with G6PD deficiency. The decrease of phenotype frequency of each HLA antigen was found to be directly proportional to the decrease of G6PD deficiency frequencies and related to environmental altitude, which is very typical for this selected group of carriers of this deficiency.