Genetic heterogeneity at the glucose-6-phosphate dehydrogenase locus in southern Italy: a study on a population from the Matera district.

Glucose-6-phosphate dehydrogenase (G6PD) has been analyzed by gel electrophoresis and by quantitative assay in an unselected sample of 1524 schoolboys from the province of Matera (Lucania) in southern Italy. We have identified 43 subjects with a G6PD variant. Of these, 31 had severe G6PD deficiency, nine had mild to moderate deficiency, and three had a non-deficient electrophoretic variant. The overall rate of G6PD deficiency was 2.6%. The frequency of G6PD deficiency, ranging from 7.2% on the Ionian Coast to zero on the eastern side of the Lucanian Apennines, appears to be inversely related to the distance of each town examined from the Ionian Coast, suggesting that this geographic distribution may reflect, at least in part, gene flow from Greek settlers. Biochemical characterization has shown that most of the G6PD deficiency in this population is accounted for by G6PD Mediterranean. In addition, we have found several examples of two other known polymorphic variants (G6PD Cagliari and G6PD A-); three new polymorphic variants, G6PD Metaponto (class III), G6PD Montalbano (class III), and G6PD Pisticci (class IV); and two sporadic variants, G6PD Tursi (class III) and G6PD Ferrandina (class II). These data provide further evidence for the marked genetic heterogeneity of G6PD deficiency within a relatively narrow geographic area and they prove the presence in the Italian peninsula of a gene (GdA-) regarded as characteristically African.