Determination of C20-C30 fatty acids by reversed-phase chromatographic techniques: an efficient method to quantitate minor fatty acids in serum of patients with adrenoleukodystrophy.

An analytical method for the determination of saturated very long chain (VLC) fatty acids in the serum has been devised. Free fatty acids obtained after hydrolysis of total lipid extracts were converted into p-bromophenacyl esters. The derivatives were purified in two sequential steps by clean-up on C18 reversed-phase cartridge and fractionation by reversed-phase thin-layer chromatography (TLC), and then quantitated by high performance liquid chromatography (HPLC) analysis. This technique provides a reliable and alternative method for the biochemical identification of patients and carriers of an inherited metabolic disease characterized by the accumulation of saturated VLC fatty acids (C24-C26) such as Adrenoleukodystrophy (ALD). In four cases of diagnosed ALD the fatty acid composition of serum total lipids was dramatically enriched in saturated VLC fatty acids compared to controls. The ratio of hexacosanoic acid (C26:0) to docosanoic acid (C22:0) in ALD patients was approximately six-fold higher than that of healthy controls or patients affected by metabolic or neurological disorders other than ALD.