Determination of total fatty acids in plasma: cis-5-tetradecenoic acid (C14:1 omega-9) in the diagnosis of long-chain fatty acid oxidation defects.

Abstract

The biochemical diagnosis of long-chain fatty acid (LCFA) oxidation disorders is rather difficult as there is no specific organic acid profile in urine. Elevation of cis-5-tetradecenoic acid (14 : 1ω-9) and of the corresponding C 14: 1 acylcarnitine in plasma are now known to be of diagnostic value in patients with very long-chain acyl-CoA dehydrogenase deficiency (VLCAD; McKusick 201475). Mild elevation of these compounds associated with other abnormal fatty acids has been observed in patients with multiple acyl-CoA dehydrogenase deficiency (MAD; McKusick 231680) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency (McKusick 600890) (Costa et al 1998; Onkenhout et al 1995). However, in our experience, in some VLCAD patients in very good condition, C 14: 1 ω-9 was barely detectable in the free fatty acid (FFA) pool (Martinez et al 1997). We measured this metabolite in total fatty acids (TFA) of plasma from 19 patients with defects of LCFA oxidation.