Complex {III} deficiency due to an in-frame MT-CYB deletion presenting as ketotic hypoglycemia and lactic acidosis

摘要

Abstract Complex {III} deficiency due to a MT-CYB mutation has been reported in patients with myopathy. Here, we describe a 15-year-old boy who presented with metabolic acidosis, ketotic hypoglycemia and carnitine deficiency. Electron transport chain analysis and mitochondrial {DNA} sequencing on muscle tissue lead to the eventual diagnosis of complex {III} deficiency. This case demonstrates the critical role of muscle biopsies in a myopathy work-up, and the clinical efficacy of supplement therapy.