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Serum branched-chain amino acids in the diagnosis of hyperinsulinism in infancy
Insights
Fasting branched-chain amino acids are lower in infants with hyperinsulinism. Measuring these amino acids can help diagnose hyperinsulinism by indicating low blood sugar and amino acid levels.
Area of Science:
- Biochemistry
- Pediatric Endocrinology
- Metabolic Disorders
Background:
- Fasting hypoglycemia is a common concern in pediatrics.
- Ketotic hypoglycemia and hyperinsulinism are distinct conditions presenting with low blood sugar.
- Branched-chain amino acids (BCAAs) play a role in energy metabolism.
Purpose of the Study:
- To investigate fasting BCAA levels in normal children, those with ketotic hypoglycemia, and infants with hyperinsulinism.
- To determine if BCAA concentrations correlate with blood glucose and insulin levels.
- To assess the utility of BCAA measurements as a diagnostic marker for hyperinsulinism.
Main Methods:
- Column chromatography was used to measure fasting serum concentrations of valine, leucine, and isoleucine.
- Blood glucose, insulin, and beta-hydroxybutyrate levels were measured concurrently.
- Statistical analysis, including correlation and comparison between groups, was performed.
Main Results:
- Normal children and those with ketotic hypoglycemia showed a negative correlation between BCAAs and blood sugar.
- Infants with hyperinsulinism had significantly lower BCAA concentrations, independent of blood sugar or insulin levels.
- BCAA sum positively correlated with blood beta-hydroxybutyrate in all children studied.
Conclusions:
- Low fasting BCAA concentrations are characteristic of hyperinsulinism.
- BCAA measurement serves as a useful physiological indicator for diagnosing hyperinsulinism in infants.
- This finding aids in differentiating hyperinsulinism from ketotic hypoglycemia.
Abstract:
Fasting values of branched-chain amino acids (valine, leucine, and isoleucine) were measured by column chromatography in the sera of 27 normal infants and children, 15 days to 9 years of age, 14 children with documented ketotic hypoglycemia one to 7 years of age, and in 14 sera from six infants, 15 days to 2 years of age, with documented hyperinsulinism. In normal children and those with ketotic hypoglycemia, each individual branched-chain amino acid and their sum were significantly negatively correlated with blood sugar values ranging between 11 and 92 mg/dl (P < 0.001). In infants with hyperinsulinism, branched-chain amino acid concentrations were significantly lower (P < 0.001) without correlation with blood sugar values ranging between 13 and 51 mg/dl, and plasma insulin concentrations (9 to 85 microU/ML). In all the children the sum of branched-chain amino acids was positively correlated with blood beta OH butyrate concentrations measured at the same time (r = 0.75, P < 0.001). The association of low blood sugar and low branched-chain amino acid concentrations during fasting seems characteristic of hyperinsulinism, and the measurement of branched-chain amino acids in these infants offers a physiologic indicator of the diagnosis of hyperinsulinism.