Muscle carnitine deficiency in old age. Case report and therapeutic results.

A muscle carnitine deficiency was discovered in a 67-year-old retired factory worker with a clinical picture of late-onset myopathy. The diagnosis was made by muscle biopsy and free carnitine assay. Therapy including a medium chain triglycerides diet and 6 g/day of D, L-carnitine per os produced a remarkable clinical improvement confirmed by a control muscle biopsy 15 months later. Our patient is the oldest one described with muscle carnitine deficiency. The differential diagnosis of a late-onset myopathy should include lipid myopathies, some of which can be treated successfully.