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Clinical Observation
November 12, 2001

mtDNA Disease in the Primary Care Setting

Author Affiliations

From the Department of Medicine, Harbor-UCLA Medical Center (Drs Spellberg, Carroll, and Brass), and UCLA School of Medicine (Mr Robinson and Dr Brass), Torrance, Calif. Dr Brass is a consultant to Sigma Tau Pharmaceuticals, Gaithersburg, Md, the manufacturer of L-carnitine.

Arch Intern Med. 2001;161(20):2497-2500. doi:10.1001/archinte.161.20.2497

Disorders of mitochondrial DNA (mtDNA) may commonly present to primary care physicians but go undiagnosed. A 36-year-old man with a 15-year history of psychosis, seizures, and sensorineural hearing loss and a family history of diabetes mellitus and heart disease presented to our hospital without a unifying diagnosis. Physiologic, biochemical, and genetic testing revealed deficient aerobic metabolism, a defect in mitochondrial electron transport, and the presence of an A-to-G point mutation at position 3243 of the mitochondrial leucine–transfer RNA gene, establishing the diagnosis of mitochondrial encephalopathy, lactic acidosis, and strokelike syndrome (MELAS). Diagnosing mtDNA disorders requires a careful integration of clinical signs and symptoms with pedigree analysis and multidisciplinary testing. Diagnosis is important to provide genetic counseling, avoid unnecessary evaluation, and facilitate therapy for symptomatic relief.