Chronic progressive external ophthalmoplegia (CPEO) is a rare mitochondrial ocular disorder.
The entity can manifest in isolation or as a syndrome with other neurological deficits, the latter of which is referred to as CPEO+. One specific syndromic variant of CPEO is Kearns-Sayre syndrome, which additionally has a pigmentary retinopathy and cardiac conduction abnormalities.
Patients either have a large deletion of mitochondrial DNA or multiple deletions due to mutations in nuclear genes that affect mitochondrial DNA repair or replication 1.
Patients show variable levels of mild to moderate extraocular muscle atrophy (25-60% volume loss compared to normal controls) 1-3. The findings should be bilaterally symmetric.
Some affected patients show extraocular muscle signal abnormalities, including T1 hyperintensity and very occasionally STIR hyperintensity 3. The T1 hyperintensity appears spongiform or like streaks within the muscle 2,3.
- 1. Yu-Wai-Man C, Smith FE, Firbank MJ, Guthrie G, Guthrie S, Gorman GS, Taylor RW, Turnbull DM, Griffiths PG, Blamire AM, Chinnery PF, Yu-Wai-Man P. Extraocular muscle atrophy and central nervous system involvement in chronic progressive external ophthalmoplegia. (2013) PloS one. 8 (9): e75048. doi:10.1371/journal.pone.0075048 - Pubmed
- 2. Ortube MC, Bhola R, Demer JL. Orbital magnetic resonance imaging of extraocular muscles in chronic progressive external ophthalmoplegia: specific diagnostic findings. (2006) Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus. 10 (5): 414-8. doi:10.1016/j.jaapos.2006.04.012 - Pubmed
- 3. Pitceathly RD, Morrow JM, Sinclair CD, Woodward C, Sweeney MG, Rahman S, Plant GT, Ali N, Bremner F, Davagnanam I, Yousry TA, Hanna MG, Thornton JS. Extra-ocular muscle MRI in genetically-defined mitochondrial disease. (2016) European radiology. 26 (1): 130-7. doi:10.1007/s00330-015-3801-5 - Pubmed