Long-chain polyunsaturated fatty acid status in phenylketonuric patients treated with tetrahydrobiopterin

Objectives:To evaluate LCPUFA composition in PKU patients treated with BH4.Design and methods:Cross-sectional study of plasma and erythrocyte LCPUFA composition of 13 PKU patients treated with BH4 compared with data from 48 PKU patients on protein-restricted diet, and 17 mild HPA patients on free diet. PUFA were analysed by gas chromatography.Results:Plasma and erythrocyte docosahexaenoic acid (DHA), and LCPUFA deficiency markers did not show significant differences in PKU patients on BH4 compared with those with mild HPA and our reference values, but they did in comparison with PKU on protein-restricted diet (p < 0.0001). Essential fatty acids and arachidonic acid composition were not significantly different in any of the studied groups. DHA values correlate with the index of dietary control only in PKU patients on protein-restricted diet (p =   0.002).Conclusion:LCPUFA status is within the reference values in PKU patients treated with BH4. This translates to a further advantage of BH4 therapy.