[Differential congenital myasthenia syndrome diagnosis].

Among myopathies and disorders of neuromuscular transmission, the congenital myasthenic syndromes (CMS) are particularly rare. However, because of the available therapeutic options, it is still clinically important to achieve a correct diagnosis in these patients. We report an adult patient with ophthalmoplegia and nonfluctuating limb-girdle syndrome. For almost 20 years, a congenital myopathy or mitochondriopathy had been suspected before CMS was diagnosed caused by an epsilon subunit mutation of the acetylcholine receptor (epsilon1276delG).