Abstract
Carnitine is essential nutrient obtained from the diet and also biosynthesized from the essential amino acids lysine and methionine. The established function of carnitine is as a carrier of activated fatty acids and activates acetate across the inner mitochondrial membrane. Other roles of carnitine include buffering of the acyl coenzyme A - CoA ratio, removal of excess acyl groups, and peroxisomal fatty acid oxidation and also influences carbohydrate metabolism. Primary carnitine deficiency (PCD) is an autosomal recessive disorder of fatty acid oxidation caused by deficiency of plasma membrane carnitine resulting from impairment in the plasma membrane transporter, leading to decreased accumulation in the skeletal muscle, heart and potentiates increased renal loss leading to systemic carnitine depletion. Recent studies have revealed Secondary carnitine deficiencies (SCD) occur due to an accumulation of organic acids, characterized by carnitine increased excretion in urine in the form of acyl-carnitine and SCD associated with more common disorders like Diabetes mellitus, hemodialysis, trauma, malnutrition, cardiovascular diseases, obesity, Alzheimer’s disease, AIDS and cancer. Allow us to tease out additional pathways dependent on carnitine functions. In this review, we present current knowledge of carnitine biology in health and disease. This article is part of a special issue entitled: Metabolic Functions and Biogenesis of Carnitine in Health and Disease.