ExtractThe intermediates of the glycolytir pathway were investigated in erythroeytes of children with Down's syndrome and the results achieved were compared with those obtained from healthy children of the same age. In the acid-soluble fraction obtained from the erythroeytes, the levels of the intermediates of the glycolytic pathway were determined. The adenine and guanine nucleotides, coenzymes, and inorganic phosphate (Pi) and some other intermediates were examined. The adenine nucleotides: adenosine 5'-monophosphate (AMP), adenosine o'-diphosphate (ADP), adenosine o'-triphosphate (ATP) and the guanine nucleotide: guanosine fZ-triphosphate (GTP) were determined. The nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), two glycolytic pathway coenzymes, were examined. Hexose diphosphate (HDP) and 2,3-diphosphoglyceric acid (2,3-DPG) were tested.Three groups were distinguished after the determination of the karyotype in the children examined: group I, seven children with Down's syndrome and trisomy G (karyotype 47,XX,G+ or 47,XY,G +); group II, two children (siblings) with Down's syndrome and G/G translocation (karyotype 46,XX,G —, t(GqGq) +mat or 46,XY, G —, t(GqGq) +mat); and group III, healthy children with a normal karyotype, corresponding to the sex. The results of the biochemical investigations in all of the three groups were compared.Taking the values obtained for the healthy children as standard, a considerable decrease in the levels of ATP and 2,3-DPG and an increase in the levels of AMP, GTP, NAD, NADP, Pi, and HDP were noticed in the group of children with Down's syndrome and trisomy G. The ADP concentration was the same as in the control group. The values of some intermediates obtained for the group of mongols with unbalanced translocation G/G were approximately the same as the values obtained for the group of mongols with trisomy G. The 2,3-DPG level was just as low as in the mongol group with trisomy G.The results of the calculations, developed by means of the Student test, are statistically significant.SpeculationThe levels of the glycolytic pathway intermediates in erythroeytes of children with Down's syndrome deviate from normal. The differences which were observed may reflect disturbances of enzymatic activity. It is also possible that these differences are aresult of nutritional disturbances or are caused by the incidence of a population of atypical erythrocytes.