We review here some recent data about Glucose-6-phosphate dehydrogenase (G6PD), the housekeeping
X-linked gene encoding the first enzyme of the pentose phosphate pathway (PPP), a NADPH-producing dehydrogenase.
This enzyme has been popular among clinicians, biochemists, geneticists and molecular biologists because it is the
most common form of red blood cell enzymopathy. G6PD deficient erythrocytes do not generate NADPH in any other
way than through the PPP and for this reason they are more susceptible than any other cells to oxidative damage.
Moreover, this enzyme has also been of crucial importance in many significant discoveries; indeed, G6PD polymorphisms
have been instrumental in studying X-inactivation in the human species, as well as in establishing the clonal nature of
G6PD deficiency, generally considered as a mild and benign condition, is significantly disadvantageous in certain
environmental conditions like in presence of certain drugs. Nevertheless, G6PD deficiency has been positively selected by
malaria, and recent knowledge seems to show that it also confers an advantage against the development of cancer, reduces
the risk of coronary diseases and has a beneficial effect in terms of longevity.