The possible role of the glucose-6-phosphate dehydrogenase enzyme deficiency in the polyneuropathies

Abstract

Glucose is the main energy source of the various types of cells and largely metabolized by either glycolysis or pentose phosphate pathway (PPP). Glucose-6-phosphate dehydrogenase (G6PD, glucose 6-phosphate (G6P): NADP (+) oxidoreductase, EC 1.1.1.49) is the first and rate limiting enzyme of the oxidative branch of the PPP. This enzyme found in many species from bacteria to humans and is found in all cell types. G6PD deficiency is the most common enzyme deficiency affecting 400 million people worldwide. However, moderate G6PD deficiency may not give symptoms but can lead to various neurological and neurodegenerative disorders including polyneuropathies. Both inflammation and oxidative stress play a major role in the formation of the neurological disorders, however, G6PD gives advantage to brain and nerve cells to fight against oxidative stress, neurodegeneration, neuronal survival and aging. In conclusion, G6PD plays vital role to maintain homeostasis of lipid, redox and energy metabolisms. Thus, impairment in the G6PD activity may cause elevated levels of oxidative stress involved in the formation of the neurodegeneration and may involve in the primary cause of idiopathic sensory-motor polyneuropathy.