Résumé :
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External ophthalmoplegia (EO), although often present in various neuromuscular diseases, is not usually observed in muscular dystrophies except for oculopharyngeal muscular dystrophy. We report on 37-year-old man, healthy until age 25, affected with non fluctuating asymmetric blepharoptosis, bilateral upward and lateral gaze limitation without diplopia, and exophthalmos . He had also difficulty in standing up from the floor, reduced strength of flexors of the tights and extensors of the feet, bilateral winging of the scapulae, hypertrophy of calf muscles, hypotrophy of quadriceps and pectoralis muscles. Serum CK levels were three to seven times the normal values; anti- acetylcholine receptor antibodies were negative; lactic acid and thyroid function were normal. Electromyography showed myopathic changes and repetitive nerve stimulation was normal. Brain and orbital magnetic resonance imaging was normal. Biopsy of left deltoid muscle showed variability of muscle fibre size with hypertrophic and atrophic fibres, internal nuclei, few necrotic or degenerating fibres, fibre splitting and mild endomisial fibrosis. Immunohistochemistry and Western Blot analysis showed a complete absence of caveolin-3 protein. Sequence analysis of the caveolin-3 gene revealed a heterozygous substitution of C to T at codon 314 of the caveolin-3 gene, changing Pro to Leu at the position 105 of the mature protein. We suggest that LGMD1C should be add to the list of conditions that cause EO.. Since limb weakness in LGMD1C may not be evident, caveolin-3 involvement should be considered in the differential diagnosis of myogenic external ophtalmoplegia.
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