Definition:

Systemic primary carnitine deficiency is a rare autosomal recessive disorder characterized by cardiomyopathy, muscle weakness, hypoglycemic hypoketotic coma, and hyperammonemia. Carnitine plays essential roles in the transportation of long-chain fatty acids into the mitochondria for beta-oxidation. This disease is caused by mutations in SLC22A5 that encodes the high-affinity sodium-dependent carnitine transporter, organic cation transporter 2 (OCTN2). The hallmark of systemic primary carnitine deficiency is low concentrations of carnitine in plasma, with accumulation of lipid deposits and renal leakage of carnitine. The clinical symptoms are alleviated dramatically by oral administration of L-carnitine. However, if untreated, patients are precipitated into a crisis with cardiac arrest or Reye-like syndrome that includes acute encephalopathy and fatty degenerative liver failure.