Red blood cell glucose metabolism in trisomy 10p: Possible role of hexokinase in the erythrocyte

Red blood cell glucose metabolism was investigated in a male patient with de novo trisomy 10p. According to previous evidence, when assigning hexokinase gene locus in the 10p11 → pter region, a triplex dosage effect of hexokinase activity (HK) was found, while all the other erythrocyte glycolytic enzymes were in the normal values range. Red blood cell glucose utilization was 2.87 μmole/hr/ml RBC as compared to 1.43 in normal controls; the rate of glucose metabolized through the hexose monophosphate shunt (HMPS) was unchanged. Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, and dihydroxyacetone phosphate increased with respect to normal controls, while normal levels of 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, and ATP were found. The HK activity increased in all red blood cell fractions obtained by density gradient ultracentrifugation. However, a small difference in the distribution of cells through the gradient was evident. The experiments reported in this article show that in the red blood cells of patients with trisomy 10p, an increased level of HK leads to higher concentrations of glucose-6-phosphate and to a faster glucose utilization in the Embden-Meyerhof pathway, while the HMPS rate is unchanged.