Table 2.
Aberrant Sugar and Polyol Metabolites in Plasma and Deficient Transketolase Enzymatic Activity
|
Subject |
Control Values | |||||
|---|---|---|---|---|---|---|
| I.1 | I.2 | II.1 | II.2 | III.1 | ||
| Age (years) | 8 | 5 | 20 | 11 | 24 | – |
| Plasma Polyol and Sugar Metabolites (μmol/L) | ||||||
| Threitol | <5 | <5 | 6 (↑) | <5 | 7 (↑) | 0–5 |
| Erythritol | 28 (↑) | 28 (↑) | 60 (↑) | 28 (↑) | 56 (↑) | 0–5 |
| Arabitol | 18 (↑) | 18 (↑) | 111 (↑) | 93 (↑) | 44 (↑) | 0–5 |
| Ribitol | 13 (↑) | 14 (↑) | 80 (↑) | 45 (↑) | 40 (↑) | 0–5 |
| Myo-inositol | 18 (↓) | 17 (↓) | 30 | 19 (↓) | 19 (↓) | 21–49 |
| Xylulose | <5 | <5 | <5 | <5 | <5 | 0–5 |
| Ribose | <5 | <5 | 25 (↑) | 29 (↑) | interferencea | 0–5 |
| Xylitol | <5 | <5 | <5 | <5 | <5 | 0–5 |
| Enzyme Studies (nmol/mg Protein/Minute) | ||||||
| Erythrocyte transketolase | – | – | minimal detectable activity | minimal detectable activity | – | – |
| Lymphoblast transketolase | 4.7 | 4.8 | – | – | – | 12.7–31.3 |
| Fibroblast transketolase | – | – | – | – | no detectable activity | 12.1–17.8 |
Sugars and polyols were analyzed in urine and plasma by gas-chromatography as described.11 Transketolase activity was measured enzymatically in lymphoblast, fibroblast, and erythrocyte extracts as previously described.12 ↑, elevated;↓, decreased.
a
The peak in the chromatogram is disturbed by another peak and therefore cannot be quantified.