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MCAT

Unit 2: Lesson 3

Foundation 3: Organ Systems

Hypoglycemia and carbohydrate metabolism

Problem

A mother brings her two-year-old son to the pediatrician, after noticing that he appears to be “clammy and fussy” a couple hours after feeding in recent months. “He’s vomited a couple 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.
On physical exam, 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 5th percentile. The physician recommends that the boy undergo a carefully monitored fast at the hospital to test for the development of 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 appropriately maintain blood glucose levels after a meal. She orders that a specimen of the boy’s liver be analyzed for possible enzyme deficiencies in the metabolism of glucose. The partial results of the lab studies are shown in the table below.
Name of EnzymeIs the enzyme involved in glycolysis?Is the enzyme involved in gluconeogenesis?Is the enzyme deficient or normal?
YesNo
YesYes
NoYes
Table 1. The boy's lab results
The pediatrician diagnoses the patient with a deficiency in an enzyme that alters the phosphorylation state of a metabolite in gluconeogenesis. Based on your understanding of carbohydrate metabolism and the clinical picture outlined in the passage, which of the following is most likely TRUE?
Choose 1 answer:
Choose 1 answer:
Stuck?
Stuck?