Different polymorphic variants of glucose-6-phosphate dehydrogenase (G6PD) in Italy.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is common in Italy and recent biochemical and kinetic studies have demonstrated the presence of polymorphic variants associated with severe or mild enzyme deficiency. We performed a biochemical characterization of G6PD in a large number of Italian G6PD deficient men in an attempt to identify the most reliable biochemical indices for discriminating polymorphic G6PD variants and to define their distribution throughout the country. Three polymorphic G6PD variants, respectively named Mediterranean, Cagliari and Sassari, were identified. The elution profile on DEAE-Sephadex column chromatography, substrate analogue utilization and the Michaelis constant for G6P were the most significant parameters to discriminate polymorphic variants among the variants with activity levels lower than 0.8 IU/g Hb. The distribution of the polymorphic variants, in relation to the origin of the subjects studied, differs throughout the country.