Case of X-linked myopathy with excessive autophagy.

We report a 12-year-old boy with a vacuolar myopathy with clinical and histologic features of X-linked myopathy with excessive autophagy. This is a rare and slowly progressive disease of skeletal muscle without cardiac, nervous system, or other organ involvement. The differential diagnosis of vacuolar myopathy includes acid maltase deficiency, Danon disease, and X-linked myopathy with excessive autophagy.