Autonomic symptoms in carriers of the m.3243A>G mitochondrial DNA mutation

Abstract

Background: The m.3243A>G mutation can cause multisystem medical problems and can affect the autonomic nervous system. Objective: To study the frequency and spectrum of autonomic symptoms associated with the m.3243A>G mitochondrial DNA point mutation. Design, Setting, and Patients: We studied a cohort of 88 matrilineal relatives from 40 families, including 35 fully symptomatic patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS), 53 carrier relatives, and 16 controls using a questionnaire based on existing standard instruments for the evaluation of autonomic dysfunction. We compared the questionnaire with an expert evaluation. We compared data among the 3 groups using the Mantel-Haenszel χ2 test to determine the statistical significance of differences between groups. Results: Mutation carriers frequently had symptoms of autonomic dysfunction, specifically gastrointestinal and orthostatic intolerance. Conclusions: Carriers of the m.3243A>G mutation have frequent autonomic symptoms. The m.3243A>G mutation should be considered as an etiological factor in patients with autonomic dysfunction and amedical or family history suggestive of mitochondrial disease. Because some autonomic symptoms are treatable, early detection and proactive management may mitigate the burden of morbidity. ©2010 American Medical Association. All rights reserved.