Migraine in mitochondrial disorders: Prevalence and characteristics.

Background Migraine is a well-known feature of mitochondrial disorders (MDs). However, no systematic epidemiological data are available in large populations of patients. Aims The aim of this cross-sectional cohort study was to describe the prevalence and migraine characteristics in a large cohort of patients with mitochondrial encephalomyopathies. Methods We studied 93 consecutive patients with characterised MDs referred to our Neuromuscular Unit during a 12-month period. All patients (age range = 16-78 years; 31 men; 58 progressive external ophthalmoplegia [PEO], 12 myoclonic epilepsy with ragged red fibres [MERRF], eight mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes [MELAS], two mitochondrial neurogastrointestinal encephalomyopathy [MNGIE] and 13 other MDs) underwent a structured diagnostic headache interview using an operational diagnostic tool following the IHS criteria. If they met the criteria for migraine, they were included in the 'Migraine Group'. The other patients were counted in the 'No Migraine Group'. Patient demographic and migraine characteristics were examined. Clinical, neuroradiological and neurophysiological data were compared between groups. Results Migraine was reported in 35.5% of patients. Migraine without aura was the most common headache (81.8%). The migraine group showed younger age ( P < 0.01), increased prevalence of epilepsy ( P = 0.01), myoclonus ( P = 0.03), stroke-like episodes ( P = 0.03) and decreased prevalence of muscle weakness ( P < 0.01). Multivariate analysis showed that migraine was positively associated with absence of muscle weakness ( P = 0.04) and presence of EEG abnormalities ( P = 0.02). Conclusion Migraine has a higher prevalence in MDs compared with general population-based data, independently from genotype or phenotype. Migraine is not merely a phenotypic aspect of specific MDs but is rather the expression of vulnerability of the central nervous system, probably directly related with defects of the respiratory chain.