Red cell glucose-6-phosphate dehydrogenase deficiency in Finland. Characterization of a new variant with severe enzyme deficiency.

Severe red cell glucose-6-phosphate dehydrogenase (G-6-PD) deficiency has been found in an 'aboriginal' Finnish family. 2 male and 9 female carriers of the variant G-6-PD were studied. The genetic pattern is consistent with x-linked recessive inheritance and the defect is associated with drug (primaquine) induced haemolysis. This was demonstrated by enzyme deficient red cell (51Cr-labelled) survival studies on a normal volunteer recipient. In addition, one of the hemizygotes studied had a slight chronic nonspherocytic haemolytic disorder. The partially purified enzyme had many of the characteristics of G-6-PD Mediterranean. The occurrence of this G-6-PD Mediterranean type variant in the Finnish population, which differs greatly from Mediterranean ethnic groups, as well as the association of slight chronic haemolysis with severe G-6-PD deficiency is discussed.