AssessmentsGlycogen storage disease type IV
Glycogen storage disease type IV
USMLE® Step 1 style questions USMLE
A 10-month female infant is brought the emergency department because of progressive abdominal distension. Medical history is significant for growth delay. On physical examination, the patient shows marked hepatomegaly, fluid wave sign, and shifting dullness. Her temperature is 36.5°C (98°F), pulse is 107/min, respirations are 16/min, and blood pressure is 120/70 mmHg. Laboratory studies show increased prothrombin time and partial thromboplastin time. A wedge biopsy of the liver shows positive periodic acid–Schiff stain, portal fibrosis, and fibrous septa. A deficiency of which of the following enzyme activities is the most likely cause of the findings in this patient?