(MC â 0.25) A 6-month-old Caucasian boy becomes ill after fruits and vegetables are added to his diet of breast milk. Mother feels that he used to become colicky when she ate fruit, although her pediatrician did not think this was significant. After 1 month of these new foods, the child has stopped gaining weight and the pediatrician feels an enlarged liver. Initial blood tests show a mild acidosis (pH 7.2) with increased lactic acid and low blood glucose. The urine reagent strip test reaction is positive for reducing substances in the urine, but the glucose oxidase test is negative for glucosuria. A glycogen storage disease is suspected, and a liver biopsy dose shows mildly increased glycogen with marked cellular damage suggestive of early cirrhosis. Assays for type IV glycogen storage disease are negative, and the initial frozen urine sample is reanalyzed and found to contain fructose. The most likely diagnosis and the reasons for hypoglycemia and glycogen accumulation is which of the following?
A. Hereditary fructose intolerance with inhibition of liver phosphorylase
B. Hereditary fructose intolerance with inhibition of glycogen synthase
C. Essential pentosuria with inhibition of liver phosphorylase
Please explain why the correct answer is correct, and what makes the other wrong.
(MC â 0.25) A 6-month-old Caucasian boy becomes ill after fruits and vegetables are added to his diet of breast milk. Mother feels that he used to become colicky when she ate fruit, although her pediatrician did not think this was significant. After 1 month of these new foods, the child has stopped gaining weight and the pediatrician feels an enlarged liver. Initial blood tests show a mild acidosis (pH 7.2) with increased lactic acid and low blood glucose. The urine reagent strip test reaction is positive for reducing substances in the urine, but the glucose oxidase test is negative for glucosuria. A glycogen storage disease is suspected, and a liver biopsy dose shows mildly increased glycogen with marked cellular damage suggestive of early cirrhosis. Assays for type IV glycogen storage disease are negative, and the initial frozen urine sample is reanalyzed and found to contain fructose. The most likely diagnosis and the reasons for hypoglycemia and glycogen accumulation is which of the following?
A. Hereditary fructose intolerance with inhibition of liver phosphorylase
B. Hereditary fructose intolerance with inhibition of glycogen synthase
C. Essential pentosuria with inhibition of liver phosphorylase
Please explain why the correct answer is correct, and what makes the other wrong.
