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Multisystem disorder in late-onset chronic progressive external ophthalmoplegia
Gerald Pfeffer1, Sandra Sirrs, N Kevin Wade
1Division of Neurology, University of British Columbia, Vancouver.
Summary
Late-onset chronic progressive external ophthalmoplegia (CPEO) presents with frequent multisystem dysfunction, unlike typical mitochondrial syndromes. Acquired mitochondrial toxicity may contribute to adult-onset CPEO.
Area of Science:
- Neurology
- Mitochondrial Medicine
- Genetics
Background:
- Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial disorder within the Kearns-Sayre syndrome (KSS) spectrum.
- Phenotypic variability in CPEO, particularly with late-onset, necessitates further investigation.
Purpose of the Study:
- To describe the clinical characteristics of patients with late-onset CPEO.
- To identify differences in phenotype and potential contributing factors in adult-onset CPEO compared to previously reported cases.
Main Methods:
- Retrospective chart review of 40 patients diagnosed with late-onset CPEO.
- Analysis of clinical features, laboratory results, and neurophysiological findings.
Main Results:
- Multisystem involvement was common, with gastrointestinal dysfunction (60%) and migraine headaches (40%) being prevalent.
- Classical KSS features like pigmentary retinopathy (2.5%) and cardiac conduction abnormalities (5%) were rare; endocrinopathy (22.5%) was more common.
- Neurophysiological testing revealed length-dependent axonal polyneuropathy (44%) and myopathic EMG changes (26%).
- Higher than expected prevalence of acquired mitochondrial toxicity factors, including smoking and Hepatitis C infection.
Conclusions:
- Late-onset CPEO exhibits a distinct phenotype compared to earlier reports, characterized by increased multisystem dysfunction.
- Classical mitochondrial manifestations are less frequent in adult-onset CPEO.
- Acquired mitochondrial toxicity is suggested as a potential contributing factor in the pathogenesis of adult-onset CPEO.
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