title: Complex III deficiency due to an in-frame MT-CYB deletion presenting as ketotic hypoglycemia and lactic acidosis.
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.
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA.
authors.forename: Mari
authors.initials: M
authors.lastname: Mori
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA; Biochemical Genetics Laboratory, Duke University Medical Center, Durham, NC, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Goldstein
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA; Biochemical Genetics Laboratory, Duke University Medical Center, Durham, NC, USA.
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Young
authors.affiliation: Department of Pathology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Bossen
authors.affiliation: Department of Medical Neurogenetics, Atlanta, GA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Shoffner
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA; Biochemical Genetics Laboratory, Duke University Medical Center, Durham, NC, USA.
authors.forename: Dwight D
authors.initials: DD
authors.lastname: Koeberl
keywords: CK, creatine phosphokinase; CSF, cerebrospinal fluid; Carnitine deficiency; Complex III deficiency; Cytochrome b; ETC, electron transport chain; G-tube, gastric feeding tube; GSD, glycogen storage disease; Ketotic hypoglycemia; MCT, medium chain triglyceride; MRS, magnetic resonance spectroscopy; Mitochondrial myopathy; mtDNA, mitochondrial DNA