A novel vacuolar myopathy with dilated cardiomyopathy.

We report a 46-year-old male patient with late-onset vacuolar myopathy and dilated cardiomyopathy. Acid maltase activity of the muscle was normal, but the biopsied muscle specimen stained for lysosome-associated membrane protein-2 (LAMP-2), which has recently been reported to be deficient in muscles of patients with Danon disease. The clinical features of the patient are distinct from X-linked myopathy with excessive autophagy, infantile autophagic vacuolar myopathy and autophagic vacuolar myopathy with late-onset and multiorgan involvement (Kaneda).