Protein-sensitive and fasting hypoglycemia in children with the hyperinsulinism/hyperammonemia syndrome.

Abstract

OBJECTIVE:

Because the hyperinsulinism/hyperammonemia (HI/HA) syndrome is associated with gain of function mutations in the leucine-stimulated insulin secretion pathway, we examined whether protein feeding or fasting was responsible for hypoglycemia in affected patients.

STUDY DESIGN:

Patients with HI/HA (8 children and 6 adults) were studied. All had dominantly expressed mutations of glutamate dehydrogenase and plasma concentrations of ammonium that were 2 to 5 times normal. The responses to a 24-hour fasting test were determined in 7 patients. Responses to a 1.5 gm/kg oral protein tolerance test in 12 patients were compared with responses of 5 control subjects.

RESULTS:

The median age at onset of hypoglycemia in the 14 patients was 9 months; diagnosis was delayed beyond age 2 years in 6 patients, and 4 were not given a diagnosis until adulthood. Fasting tests revealed unequivocal evidence of hyperinsulinism in only 1 of 7 patients. Three did not develop hypoglycemia until 12 to 24 hours of fasting; however, all 7 demonstrated inappropriate glycemic responses to glucagon that were characteristic of hyperinsulinism. In response to oral protein, all 12 patients with HI/HA showed a fall in blood glucose compared with none of 5 control subjects. Insulin responses to protein loading were similar in the patients with HI/HA and control subjects.

CONCLUSION:

The postprandial blood glucose response to a protein meal is more sensitive than prolonged fasting for detecting hypoglycemia in the HI/HA syndrome.

• Authors: B Y Hsu, A Kelly, P S Thornton, C R Greenberg, L A Dilling, C A Stanley
• Journal: The Journal of pediatrics (J Pediatr) Vol. 138 Issue 3 Pg. 383-9 (Mar 2001) ISSN: 0022-3476 [Print] United States
• PMID: 11241047 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Dietary Proteins
• Glutamate Dehydrogenase

Topics

• Adolescent
• Adult
• Age of Onset
• Case-Control Studies
• Child
• Child, Preschool
• Dietary Proteins (adverse effects)
• Fasting (adverse effects)
• Female
• Glutamate Dehydrogenase (genetics, metabolism)
• Humans
• Hyperammonemia (genetics, physiopathology)
• Hyperinsulinism (genetics, physiopathology)
• Hypoglycemia (etiology)
• Infant
• Male
• Middle Aged
• Postprandial Period
• Syndrome