Molecular heterogeneity of glucose-6-phosphate dehydrogenase (G6PD) variants in Italy

Background. Glucose-6-phosphate dehydrogenase deficiency, one of the most common human enzymatic defects, is characterized by extreme molecular and biochemical heterogeneity. The molecular bases of almost all polymorphic Italian variants have now been identified and the overall heterogeneity is lower than expected from biochemical data. Methods. We examined 161 G6PD- deficient subjects (130 males and 31 females)originating from different parts of Italy. G6PD activity and molecular characterization were determined in all the subjects analyzed. Results. We found the G6PD Mediterranean genotype in roughly 70%, G6PD Union and G6PD Seattle in about 6% and G6PD A- in 4% of the samples analyzed. G6PD S. Antioco and G6PD Cosenza were less frequent (1.2%), and single cases of G6PD Partenope and G6PD Tokyo were also detected. Conclusions. We report the frequency and distribution of the most common G6PD variants in Italy. Greater molecular heterogeneity than described by others was observed, especially in Sardinia. Among the severe deficient variants, G6PD Mediterranean has a higher prevalence in Sardinia (83%) than in continental Italy (61%), as does G6PD Union (10% and 4%, respectively). G6PD Seattle and A-, associated with mild G6PD deficiency, are by contrast more frequent in continental Italy.