A 4-month-old boy is brought to his pediatrician for a well-child visit. His parents have noticed that he has had poor growth compared to his older siblings. The boy was delivered vaginally after a normal pregnancy. His temperature is 98.8°F (37.1°C), blood pressure is 98/68 mmHg, pulse is 88/min, and respirations are 20/min. On exam, his abdomen appears protuberant, and the boy appears to have abnormally enlarged cheeks. A finger stick reveals that the patient’s fasting blood glucose is 50 mg/dL. On further laboratory testing, the patient is found to have elevated blood lactate levels, as well as no response to a glucagon stimulation test. What enzymatic defect is most likely present?
AAlpha-1,4-glucosidase
BGlycogen synthase
CAlpha-1,6-glucosidase
DGlucose-6-phosphatase
EGlycogen phosphorylase
A 12-year-old male presents to the pediatrician after two days of tea-colored urine which appeared to coincide with the first day of junior high football. He explains that he refused to go back to practice because he was humiliated by the other players due to his quick and excessive fatigue after a set of drills accompanied by pain in his muscles. A blood test revealed elevated creatine kinase and myoglobulin levels. A muscle biopsy was performed revealing large glycogen deposits and an enzyme histochemistry showed a lack of myophosphorylase activity. Which of the following reactions is not occurring in this individual?
ACleaving alpha-1,6 glycosidic bonds from glycogen
BCreating alpha-1,6 glycosidic bonds in glycogen
CBreaking down glycogen to glucose-1-phosphate
DConverting glucose-6-phosphate to glucose
EConverting galactose to galactose-1-phosphate
A 42-year-old man comes to the physician because of a 2-month history of fatigue and increased urination. The patient reports that he has been drinking more than usual because he is constantly thirsty. He has avoided driving for the past 8 weeks because of intermittent episodes of blurred vision. He had elevated blood pressure at his previous visit but is otherwise healthy. Because of his busy work schedule, his diet consists primarily of fast food. He does not smoke or drink alcohol. He is 178 cm (5 ft 10 in) tall and weighs 109 kg (240 lb); BMI is 34 kg/m2. His pulse is 75/min and his blood pressure is 148/95 mm Hg. Cardiopulmonary examination shows no abnormalities. Laboratory studies show: Hemoglobin A1c 6.8% Serum Glucose 180 mg/dL Creatinine 1.0 mg/dL Total cholesterol 220 mg/dL HDL cholesterol 50 mg/dL Triglycerides 140 mg/dL Urine Blood negative Glucose 2+ Protein 1+ Ketones negative Which of the following is the most appropriate next step in management?
AMetformin therapy
BLow-carbohydrate diet
CAspirin therapy
DACE inhibitor therapy
EInsulin therapy
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