Q. A 12-year-old girl is brought to the clinic by her mother, who expresses concern about her daughter's recurrent episodes of early morning fatigue and dizziness. The mother also reports that her daughter often complains of muscle cramps, especially after engaging in physical activities. Laboratory findings indicate mild ketonuria, but blood lactate levels are within the normal range. The girl's physical examination is unremarkable, aside from mild hepatomegaly. Based on the patient's presentation and laboratory findings, what is the most likely diagnosis?