Health Information

Hexokinase (HK) deficiency:

Hexokinase catalyses the first chemical reaction in glycolysis and it exits as isoenzymes. A genetic defect of HK leads to low concentrations of glycolytic intermediates, including 1,3-BPG, the precursor of 2,3-BPG, which binds to hemoglobin and lowers its affinity for oxygen. This effect allows hemoglobin to release oxygen normally in tissue capillaries. Patients with defective HK activity possess low levels of 2,3-BPG and their hemoglobin has an abnormally high oxygen affinity. This leads to hemolytic anemia finally.

Pyruvate kinase deficiency

The catalytic action of Pyruvate kinase results in the formation of two moles of ATP and Pyruvate from one mole of glucose. It exists as isoenzymes and genetic defects in isoenzymes subunits affect the formation of ATP in erythrocytes. Insufficient ATP production reduces the activity of ATPase, decreases the ability of erythrocytes and causes them to swell and lyse, decreases the stability of erythrocytes and causes them to swell and lyse. Hemolytic anemia is most common in Pyruvate kinase deficiency.

Glucose 6-PO4 dehydrogenase (G6PDH) deficiency

Glucose 6-phosphate dehydrogenase deficiency is an inherited linked trait. The most affected cells are RBC. Decreased activity of G6PDH impairs the synthesis of NADPH, which causes accumulation of methaemoglobin and peroxides in erythrocytes, leading to hemolysis. Patients suffering from G6PDH deficiency do not show any clinical symptoms normally. However, they develop hemolytic anemia when they are administered antimalarial or antipyretic medicines.

Essential fructosuria

In this disorder, fructose is not converted to fructose 1-PO4 due to the deficiency of the enzyme fructokinase in liver. Excess of fructose excretion in urine occurs without any symptoms. Restriction of dietary fructose is sufficient to treat these patients.

Essential pentosuria

This rare genetic disorder is related to the deficiency of an NADP dependent enzyme, xylitol dehydrogenase. Due to this enzyme defect, L-xylulose is not converted to xylitol. The affected persons produce large amounts of L-xylulose in urine. Essential pentosuria is asymptomatic and the individuals who suffer do not develop any ill effects.