Effects of polyunsaturated fatty acid diets on plasma lipids of patients with adrenomultineuronal degeneration, hepatosplenomegaly and fatty acid derangement

The effect on plasma fatty acid composition of 3-6 weeks feeding of standard diets supplemented with various ω6 polyenoic fatty acids (18 : 2, 18 : 3, 20 : 3 or 20 : 4) was studied in two young brothers with multineuronal degeneration plus. These boys had mental retardation or maldevelopment, neurosensory hearing loss, retinitis pigmentosa, progressive muscular atrophy, hepatosplenomegaly and adrenal failure. The study objectives were to localize the site of metabolic block and to assess the safety and short-term clinical effect of dietary treatment. Our studies have shown that the low plasma levels of 20 : 4ω6 can be corrected by feeding ethyl arachidonate and that no adverse effects were experienced. A diet enriched in ethyl linoleate produced no obvious increases of 18 : 2ω6 metabolites, indicating that these patients do not have a linoleate deficiency in their ω6 polyenoic fatty acid pathway. Lack of incorporation of 20 : 4ω6 and a retroconversion of 20 : 3ω6 to 18 : 2ω6 after a dihomo-γ-linolenate-enriched diet suggest that a defect of Δ5 desaturase may be involved.