Type II fiber myolysis in a patient with hypocarnitinemia.

The repeated muscle biopsy findings in a female affected by hypocarnitinemia were reported. Electron microscopic (EM) examination revealed degeneration of Type II fibers as well as lipid accumulation in Type I fibers during an episode mimicking the Reye syndrome (mRS), and no morphological abnormality in the subclinical stage. There was no previous information on myolysis of Type II fibers in patients with carnitine deficiency (CD). However, this study showed that Type II fibers were more severely affected than Type I fibers during exacerbation in patient with CD.