[Mitochondrial abnormalities and ocular myopathies with downward-spreading evolution. Apropos of 2 new cases].

Two cases, one being probably familial, of ocular myopathy are reported. In both the onset was in childhood by ptosis of the eyelids and the course lasted more than 20 years. The patients (32 and 49 years) presented involvement of the ocular muscles as well as of the facial, pharyngolaryngeal, neck and limb muscles. There was, in both cases, marked body weight loss which could not be explained by the muscular atrophy alone, and a thyroid nodule which was not accompanied by evident change in thyroid function. Muscle biopsy studies were carried out : electron microscopy showed in both cases aggregates of mitochondria exhibiting various changes ; in one case histochemistry demonstrated that these changes were confined to type 1 muscle fibres. These cases of descending ocular myopathy can be included therefore in the group of the smaller than myopathies with abnormal mitochondria greater than.