Metabolism: Medical case: Fussy child

A mother brings her two-year-old son to the pediatrician, after noticing that, in recent months, he appears to be “clammy and fussy” a couple of hours after feeding. “He’s vomited a couple of times and I even took him to the ER yesterday because he was having a seizure,” she exclaims, clearly frightened and worried about her son.

During the physical examination, the physician palpates the boy’s abdomen and finds that the boy’s liver is enlarged. She also checks the boy’s growth curve and notices that his weight percentile has fallen from about average to under the 5th percentile. The physician recommends that the boy undergo a carefully monitored fast at the hospital to test for hypoglycemia. After eating a meal, the boy’s blood glucose levels are monitored for several hours. Normal blood glucose levels are 60-150 mg/dL. The results are shown in Figure 1.

Figure 1 Glucose tolerance test results, showing glucose levels following a meal (time = 0)

Upon seeing the results, the pediatrician suggests that the boy is suffering from a metabolic disorder that does not allow him to maintain sufficient blood glucose levels after a meal. She orders that a specimen of the boy’s liver be analyzed for a series of enzyme deficiencies in the metabolism of glucose.