A 5-month-old girl is brought to the office by her mother for a health checkup. The mother states, "My baby doesn't seem to be growing much despite feeding as often as my previous children. I am worried that something is wrong with her." Physical examination shows hepatomegaly, hypotonia, and height and weight below the 10th percentile. Laboratory studies show hypoglycemia and ketoacidosis. A liver biopsy shows hepatic fibrosis without fat accumulation. Further analysis reveals abundant quantities of a multibranched polysaccharide with abnormally short outer chains within the cytosol of the hepatocytes. Which of the following enzymes is most likely deficient in this patient?

Question

A 5-month-old girl is brought to the office by her mother for a health checkup. The mother states, "My baby doesn't seem to be growing much despite feeding as often as my previous children.  I am worried that something is wrong with her."  Physical examination shows hepatomegaly, hypotonia, and height and weight below the 10th percentile.  Laboratory studies show hypoglycemia and ketoacidosis.  A liver biopsy shows hepatic fibrosis without fat accumulation.  Further analysis reveals abundant quantities of a multibranched polysaccharide with abnormally short outer chains within the cytosol of the hepatocytes.  Which of the following enzymes is most likely deficient in this patient?

Quizplus · Accepted Answer

Eductional Objective: Debranching enzyme deficiency (Cori disease) leads to accumulation of glycogen with abnormally short outer chains (limit dextrins) due to the inability to degrade alpha-1,6-glycosidic branch points.  Patients present with hypoglycemia, ketoacidosis, hepatomegaly, and muscle weakness and hypotonia.

A 5-Month-Old Girl Is Brought to the Office by Her