A Model of Glucose-6-Phosphate Dehydrogenase Deficiency in the Zebrafish

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common genetic defect and enzymopathy worldwide, affecting about 400 million people and causing acute hemolysis in persons exposed to pro-oxidant compounds like menthol, naphthalene, antimalarial drugs, and fava beans. Mouse models have not been useful because of a lack of significant response to oxidative challenge. We turned to zebrafish (Danrio rerio) embryos, which develop ex utero and are transparent, allowing visualization of hemolysis. We designed morpholinos to zebrafish g6pd that were effective in reducing gene expression as shown by western blot and G6PD enzyme activity resulting in a brisk hemolysis and pericardial edema secondary to anemia. Titration of the g6pd knockdown allowed us to generate embryos that displayed no overt phenotype until exposed to the pro-oxidant compounds 1-naphthol, menthol, or primaquine where after they developed hemolysis and pericardial edema within 48 - 72 hours. We were also able to show that g6pd morphants displayed significant levels of increased oxidative stress compared to controls. We anticipate that this will be a useful model of G6PD deficiency to study hemolysis as well as oxidative stress that occurs after exposure to pro-oxidants similar to what occurs in G6PD-deficient persons.