Question

10. What is the deficit of G6PD and the consequences in the organism for people who have deficits of this enzyme?

Answer 1

G6PD deficit means that there is deficiency of glucose 6 phosphate dehydrogenase enzyme caused by mutation in the G6PD gene coding for this enzyme. Glucose 6 phosphate dehydrogenase is an enzyme that converts glucose-6 phosphate to 6 phosphogluconolactone. NADP is reduced to NADPH, in pentose phosphate pathway. NADPH can be converted to NADP when glutathione disulphide is converted to glutathione by glutathione reductase. NADPH produced by G6PD enzyme is known to protect RBC from oxidative damage from reactive oxygen species. RBCs produce NADPH only via G6PD dehydrogenase. Thus, G6PD prevents ROS from accumulating in erythrocytes and killing them.

Mutation in G6PD gene leads to defective functioning or absence of G6PD enzyme in the organism. This will lead to reactive oxygen species accumulation in erythrocytes. Due to toxicity to erythrocytes, hemolytic anemia will result. As a result, oxygen supply to different tissues and organs will be decreased, causing oxygen starvation conditions. In newborns, there may be jaundice seen due to impaired clearance of bile. Adults will exhibit paleness, jaundice of skin and eyes, formation of darker urine, respiratory problems such as increased heart rate and shortness of breath. Severe injury may cause sepsis, although malaria mostly does not infect these people. This is because the bacteria cannot infect the preson that has deficiency of G6PD. This deficiency can also be triggered by bacterial infections and drugs such as sulfanomides, aspirin etc. Bacterial infections induce oxidative stress in the person. However, due to the G6PD deficiency, the oxidative stress cannot be effectively removed. This can lead to RBC lethality and death and development of hemolytic anemia. Humans with this deficiency have increased susceptibility to bacterial and viral infections. This susceptibility is due to decreased NADPH production in white blood cells. As a result, the WBC such as neutrophils and lymphocytes cannot effectively kill the bacteria. Thus, bacteria/viruses can grow and infect the person easily.