Question

Persons suffering from G6PD deficiency are resistant to malaria. Explain.

Answer 1

G6PD is the enzyme, glucose 6 phosphate dehydrogenase which decomposes H${}_2$O${}_2$ formed during metabolism. The deficiency of this enzyme is an inborn error of metabolism controlled by the specific gene. When persons suffering from malaria are given Primaquine. it causes haemolysis because H${}_2$O${}_2$ produced during metabolism is not decomposed due to the deficiency of G6PD enzymes. This H${}_2$O${}_2$ haemolysis the blood. The haemoglobin of haemolysed blood collects on the cell membrane and RBCs are deformed. In such distorted RBCs, malarial parasite fails to survive and multiply. It means a person suffering from G6PD deficiency are resistant to malaria. Such person is therefore favoured by natural selection in the area infected with the malarial parasite. For this reason, G6PD deficiency is found in 50% Negroes living in areas with malarial infection.