Question

10. A 6-month old girl presents with the following symptoms: lactate acidosis (elevated serum levels of lactate), elevated levels of alanine in both her urine and blood, and muscle weakness (suggesting low levels of ATP). Doctors diagnose her problem as dihydrolipoamide dehydrogenase deficiency (present in two complexes!). They attempt to treat the girl with dietary supplements of riboflavin, thiamine, and niacin. a) Explain how this enzyme deficiency gives rise to lactate acidosis. (What's backing up, and where is it going?) (3 pts) b) Explain how this enzyme deficiency gives rise to elevated levels of alanine in her urine and blood. (2 pts) c) Choose one of the three dietary supplements: riboflavin, thiamine, or niacin. Briefly explain how it might help this girl's condition. Cite the enzyme(s) that benefit from the treatment in each case. (3 pts)