Carnitine insufficiency in children with inborn errors of metabolism: prevalence and treatment efficacy.

Abstract

Carnitine is necessary for the transfer of long-chain fatty acids from the cytosol into mitochondria for subsequent β-oxidation. A carnitine deficiency results in impaired energy production from fatty acids. We reviewed the plasma level of total carnitine, free carnitine, and acylcarnitines in 1270 children with psychomotor retardation, low growth, and weight parameters. Tandem mass spectrometry (MS/MS) was applied. Low free carnitine level in plasma was used as a marker of carnitine deficiency. A total of 102 (8%) children had free carnitine level <19 μmol/L (norm 19-60 μmol/L). As a result of the subsequent investigation, hereditary diseases were diagnosed in 76 (¾) children and out of that 19 had very low free carnitine plasma level (<10 μmol/L). Fanconi syndrome, fat oxidation defects, primary systemic carnitine deficiency, mitochondrial encephalomyopathy, and Noonan syndrome were revealed in these 19 children. Efficacy of levocarnitine treatment in children with very low free carnitine level differs according to pathogenesis of diseases. The highest efficacy was observed in primary systemic carnitine deficiency.