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external ophthalmoplegia; progressive external ophthalmoplegia (PEO)
Pathology:
- ragged-red fibers (RRFs) with focal cytochrome c oxidase deficiency in skeletal muscle
Genetics:
- autosomal dominant progressive external ophthalmoplegia
a) mutations in the twinkle gene
b) defects in SLC25A4 (mitochondrial DNA deletions 2)
c) defects in POLG (mitochondrial DNA breakage syndrome)
d) defects in POLG2 (mitochondrial DNA deletions 4) multiple mitochondrial DNA deletions in skeletal muscle
- autosomal recessive progressive external ophthalmoplegia with mitochondrial DNA deletions
Clinical manifestations:
- adult onset of ptosis & weakness of the extraocular muscles & exercise intolerance (autosomal dominant form)
- progressive weakness of ocular muscles & levator palpebrae superioris
- in a minority of cases, it is associated with skeletal myopathy predominantly involving axial or proximal muscles resulting in abnormal fatigability & even permanent muscle weakness
- additional symptoms are variable, & may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, & parkinsonism
- autosomal recessive form is often associated with multisystemic disorders, is clinically more heterogeneous than the autosomal dominant form & can be more severe
General
ophthalmoplegia (ophthalmoparesis)
Database Correlations
OMIM correlations
References
UniProt :accession P12235