Chronic Progressive External Ophthalmoplegia: A Report of 2 Cases.
Rebecca J Varley, Maggie M Stoecker, Thomas J Cummings. Duke University, Durham, NC
Background: Chronic progressive external ophthalmoplegia (CPEO) is a rare mitochondrial myopathy characterized by chronic ophthalmoparesis and exercise intolerance.
Design: Two cases of CPEO diagnosed from deltoid skeletal muscle biopsies were evaluated by enzyme histochemistry, electron microscopy, PCR and Southern blot.
Results: A 65-year-old male presented with a 10 year history of progressive diplopia and lower extremity weakness. A 55-year-old female reported bilateral ptosis and blurred vision. Several years later, she experienced hoarseness, difficulty swallowing and right arm weakness. Neurological examinations showed bilateral limited elevation and abduction of each eye. Deltoid muscle biopsies showed red ragged fibers and increased number of cytochrome oxidase (COX) negative fibers. Electron microscopy showed increased numbers of morphologically abnormal mitochondria with paracrystalline inclusions, dense bodies, and concentric forms. PCR and Southern blot techniques identified multiple deletions in mitochondrial DNA.
Conclusions: Chronic progressive external ophthalmoplegia is a rare disorder of mitochondrial DNA. Ragged red fibers, increased COX negative fibers, and ultrastructurally abnormal numbers of mitochondria with paracrystalline inclusions are diagnostic features on muscle biopsies. The high volume of mitochondria in extraocular muscles results in the typical ocular findings in CPEO. There is currently no definitive treatment for the muscle weakness associated with CPEO; although, clinical trials of exercise training and coenzyme Q supplementation are being conducted in some metabolic myopathies.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 280, Wednesday Afternoon