Fat and Carbohydrate Metabolism During Exercise in Phosphoglucomutase Type 1 Deficiency

Context: Phosphoglucomutase type 1 (PGM1) deficiency is a rare metabolic myopathy in which symptoms are provoked by exercise. Objective: Because the metabolic block is proximal to the entry of glucose into the glycolytic pathway, we hypothesized that iv glucose could improve the exercise intolerance experienced by the patient. Design: This was an experimental intervention study. Setting: The study was conducted in an exercise laboratory. Subjects: Subjects were a 37-year-old man with genetically and biochemically verified PGM1 deficiency and 6 healthy subjects. Interventions: Cycle ergometer, peak and submaximal exercise (70% of peak oxygen consumption), and exercise with an iv glucose infusion tests were performed. Main Outcome Measures: Peak work capacity and substrate metabolism during submaximal exercise with and without an iv glucose infusion were measured. Results: Peak work capacity in the patient was normal, as were increases in plasma lactate during peak and submaximal exercise. However, the hear...