lucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the most common human enzyme deficiency in the world; it affects an estimated 400 million people. G6PD deficiency is also known as "favism," since G6PD deficient individuals are also sometimes allergic to fava beans. G6PD deficiency is an allelic abnormality which is inherited in an X-linked recessive fashion. The molecular data on G6PD is summarized in Table 1.
When someone has G6PD deficiency, complications can arise; hemolytic anemia and prolonged neonatal jaundice are the two major pathologies associated with G6PD deficiency. Both of these conditions are directly related to the inability of specific cell types to regenerate reduced nicotinamide adenine dinucleotide phosphate (NADPH); this reaction is normally catalyzed by the G6PD enzyme. A consequence of this is that G6PD deficient individuals are resistant to the malaria causing parasite.
In G6PD deficient individuals, anemia is usually caused by certain oxidative
drugs (see Table 2), infections, or fava beans.
When any one of these agents, or their metabolites, enters a G6PD deficient
red blood cell, hemoglobin becomes denatured, thus destroying its function
as the principal oxygen carrying molecule. In addition to being susceptible
to hemolytic anemia, G6PD deficient individuals are also predisposed to prolonged
neonatal jaundice. This can be a potentially serious problem as it can cause
severe neurological complications and even death. Several kinds of treatments
can be utilized in treating the different clinical manifestations of G6PD
deficiency. One treatment relies on preventative measures. Researchers are
currently genetically engineering the fava bean so that the causative agents
of the hemolysis will be eliminated; this will allow favic individuals to
eat fava beans.
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