Myopathy and growth failure in debrancher enzyme deficiency: improvement with high-protein nocturnal enteral therapy

Seven patients with debrancher enzyme deficiency and childhood or adolescent onset myopathy, four of whom also had growth failure, received long-term treatment consisting of high-protein enteral infusion overnight and high-protein feeds during the day for periods varying from 8 to 42 months. All patients demonstrated improvement in physical activity and endurance. Improvement in muscle strength was documented in five patients, with reversal of myopathic EMG patterns to normal in two patients and reversal of abnormal ECG findings to normal in one patient. All four patients with growth failure showed dramatic improvement in growth rates. This positive response to high-protein enteral therapy supports the concept that myopathy in debrancher enzyme deficiency is at least partly the result of reversible muscle amino acid depletion.