Much of the body's carnitine is present in skeletal muscle, where it is involved in transmembrane transfer of long-chain fatty acids into mitochondria. The fatty acids undergo beta-oxidation within the mitochondria in order to generate energy for muscle contraction. A primary carnitine disorder affecting muscle results in a myopathy.


Skeletal muscle involvement in a primary carnitine disorder may:

(1) be isolated to skeletal muscle

(2) involve both skeletal and cardiac muscle

(3) be part of aystemic disorder


Inheritance: autosomal recessive


Clinical features of myopathy associated with a primary carnitine disorder:

(1) proximal muscle weakness

(2) exercise intolerance

(3) myalgia


Disorder with Carnitine Deficiency

Carnitine Palmityl-transferase Deficiency

serum CK

often normal

elevated from rhabdomyo-lysis during fasting or strenuous exercise

muscle carnitine levels



skeletal muscle biopsy

accumulation of fatty acids and triglycerides

minimal or no lipid accumulation


Mitochondria may be increased in number and/or massively enlarged on ultrastructural studies.


To read more or access our algorithms and calculators, please log in or register.