To the Editor.
—Kieval and colleagues1 recently described a 60-year-old woman presumably heterozygous for carnitine palmityltransferase deficiency who had fixed limb-girdle weakness without known episodes of rhabdomyolysis. The investigators were unaware of other patients who had experienced a chronic myopathy associated with this disorder.Carey2 and associates described a 72-year-old woman with low carnitine palmityltransferase enzyme activity and fixed proximal muscle weakness also without rhabdomyolysis. However, this case differed as the patient manifested ophthalmoplegia and the muscle biopsy specimen showed ragged red fibers as well as paracrystalline inclusions by electron microscopy. It is uncertain if the reduced activity of the mitochondrial-bound carnitine palmityltransferase was primary, or secondary to another mitochondrial abnormality. It would be of interest if Kieval and coworkers would comment on the ultrastructural mitochondrial findings in their patient.In addition to the heterozygous state, gender may also have influenced phenotypic expression of carnitine palmityltransferase deficiency in their
Nelson KR, Davis D. Carnitine Palmityltransferase Deficiency and Fixed Muscle Weakness. Arch Neurol. 1990;47(1):13. doi:10.1001/archneur.1990.00530010019010