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Fructose-1-phosphate and fructose-1,6-bisphosphate aldolases in the small intestinal mucosa
Insights
Measuring fructose-1-phosphate aldolase (F1PA) activity in intestinal mucosa is a sensitive test for hereditary fructose intolerance (HFI). However, diagnosis requires both clinical and laboratory findings for accuracy.
Area of Science:
- Biochemistry
- Pediatric Gastroenterology
- Metabolic Disorders
Background:
- Hereditary fructose intolerance (HFI) is a metabolic disorder.
- Accurate diagnosis of HFI is crucial for patient management.
Purpose of the Study:
- To evaluate the diagnostic utility of fructose-1-phosphate aldolase (F1PA) and fructose-1,6-bisphosphate aldolase (FBPA) activity in small intestinal mucosa for detecting HFI.
- To establish reference values for F1PA and FBPA activity in nonaffected individuals.
Main Methods:
- Assay of F1PA and FBPA activity in small intestinal mucosal biopsies.
- Comparison of enzyme activities between children and adults with and without HFI.
Main Results:
- F1PA activity in HFI patients was significantly lower than in nonaffected individuals, showing distinct reference ranges.
- While F1PA activity was highly sensitive for HFI detection, some nonaffected individuals had low F1PA values.
- FBPA activity did not significantly aid in the differential diagnosis of HFI.
Conclusions:
- F1PA activity determination in intestinal mucosa is a sensitive indicator for HFI.
- The specificity of F1PA testing is not absolute, necessitating combined clinical and laboratory assessment.
- FBPA activity measurement offers limited additional diagnostic value for HFI.
Abstract:
Reference values are presented for the activity of fructose-1-phosphate aldolase (F1PA) and fructose-1,6-bisphosphate aldolase (FBPA) in the small intestinal mucosa of 32 nonaffected children, 8 nonaffected adults and 2 children with hereditary fructose intolerance (HFI). The 96% confidence limits for F1PA in children are 1.55 to 43.0 u/g protein, completely distinct from the results of the two affected children (1.3 and less than 0.1 u/g protein). With fructose-1,6-bisphosphate as subtrate, the 96% confidence limits are 10 to 324 u/g protein and the values for the two affected children, 23.7 and 9.3 u/g. Among the nonaffected children two mucosal biopsies with F1PA activities less than 1.55 u/g were found. In one mucosal biopsy among the nonaffected children an FBPA activity less than 10 u/g was recorded. The data are interpreted as indicating that the determination of F1PA activity in intestinal mucosa is a highly sensitive test in detecting individuals with HFI. However, the specifity of the test is not absolute. Diagnosis should be based on both clinical and laboratory considerations. The determination of FBPA activity in the same biopsy specimen does not contribute substantially to the differential diagnosis.