The natural history of minicore-multicore myopathy.

To determine the natural history of minicore-multicore myopathy (MMM) we studied 5 patients who were found to have this disorder from 6 to 16 years ago. Four of these patients had improved muscle strength since their original assessment and one patient had deteriorated. There were no clinical electrophysiological or pathological features that distinguished this last patient from the others. We conclude, therefore, that most patients with MMM may be expected to improve as time passes but, for unknown reasons, a minority may deteriorate. This information should be helpful to clinicians in their prognostic advice to new patients.