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

Mari Mori; Jennifer Goldstein; Sarah P Young; Edward H Bossen; John Shoffner; Dwight D Koeberl

doi:10.1016/j.ymgmr.2015.06.001

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

Mol Genet Metab Rep. 2015 Jun 30:4:39-41. doi: 10.1016/j.ymgmr.2015.06.001. eCollection 2015 Sep.

Authors

Mari Mori¹, Jennifer Goldstein², Sarah P Young², Edward H Bossen³, John Shoffner⁴, Dwight D Koeberl²

Affiliations

¹ Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA.
² Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA; Biochemical Genetics Laboratory, Duke University Medical Center, Durham, NC, USA.
³ Department of Pathology, Duke University Medical Center, Durham, NC, USA.
⁴ Department of Medical Neurogenetics, Atlanta, GA, USA.

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.

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.

Publication types

Case Reports