Update on Chronic Progressive External Ophthalmoplegia

Abstract

Mitochondrial encephalomyopathies are clinically and genetically heterogeneous disorders. External ophthalmoplegia is the most frequent symptom. Other frequently involved tissues and organs include the retina, heart, limb muscles, peripheral and central nervous system, inner ear and endocrine system. The diagnosis is based on the finding of elevated serum lactate, the characteristic histopathological changes in the muscle biopsy, and decreased activities of mitochondrial respiratory chain enzymes. In many cases, the underlying molecular defect in the mtDNA can be identified. The efficacy of pharmacological therapies (e.g., coenzyme Q) has not been established so far. Symptomatic ophthalmological treatment includes ptosis and strabismus surgery. Early cardiac pacemaker implantation may be life-saving.

Hemifacial presentation of mitochondrial myopathy

“…Although asymmetric ophthalmoplegia does occur in a minority of CPEO patients [1,7], accurate measurements of ocular motility have shown that the extent of asymmetry is very small [8]. The marked asymmetry of ophthalmoplegia in our case is therefore surprising.…”

“…CPEO is characterised by bilateral ptosis and global restriction of eye movements [1]. It is the commonest ocular manifestation of the mitochondrial myopathies and can occur in isolation or with additional non-ocular features [2,3].…”

“…Bilateral ptosis is a hallmark of CPEO and is the presenting complaint in up to 90% of cases [1]. The ptosis can be asymmetric, however [2].…”

“…Ophthalmoplegia in CPEO is usually symmetric and, in advanced cases, often complete [1]. Although asymmetric ophthalmoplegia does occur in a minority of CPEO patients [1,7], accurate measurements of ocular motility have shown that the extent of asymmetry is very small [8].…”

Mitochondrial tRNA Mutations: Clinical and Functional Perturbations

“…Chronic progressive external ophthalmoplegia (CPEO) is a myopathy characterized by paralysis of extraocular muscles (reviewed in ref. 84). Age at onset is variable, with many patients first noticing bilateral ptosis in the third or fourth decade of life.…”