Carnitine deficiency of skeletal muscle: report of a treated case.

We studied a 10-year-old girl with an insidious muscle disease beginning at age 7. Muscle biopsy showed that the majority of type I fibers were vacuolated and contained lipid excess. Carnitine deficiency was found in skeletal muscle. The patient was treated with 3.0 gm L-carnitine per day and with a medium-chain triglyceride diet. She showed a rapid improvement and recovery of strength. A muscle biopsy 8 months later showed a decreased lipid content. Oral carnitine replacement represents an effective treatment for the disease.