LONG-CHAIN POLYUNSATURATED FATTY-ACIDS IN PLASMA AND ERYTHROCYTE-MEMBRANE LIPIDS OF CHILDREN WITH PHENYLKETONURIA AFTER CONTROLLED LINOLEIC-ACID INTAKE

It has been reported that children with classical phenylketonuria (PKU ) have reduced levels of arachidonic acid (AA, 20.4 n - 6) and docosah exaenoic acid (DHA, 22.6 n - 3) in plasma and membrane phospholipids c ompared to controls and may therefore require supplementation. However , it is not established that these changes are specific for PKU. They may as well be attributed to the specific composition of a largely veg etarian diet used for dietary PKU treatment. We therefore investigated the fatty acid composition of plasma phospholipids (PL), plasma chole sterol esters (CE), red blood cell phosphatidylcholine (PC), and red b lood cell phosphatidylethanolamine (PE) in two groups of PKU patients including 8 children between 1 and 6 years (group A), 9 adolescents be tween 11 and 18 years (group B), and 20 age-matched healthy controls. Group A had good dietary control (median plasma phenylalanine 272 mu m ol/L during the last 6 months before phospholipid analysis) while medi an phenylalanine in group B was 714 mu mol/L (p < 0.001). When compare d to age-matched controls, group A showed significantly lower DHA leve ls in PE (4.21 vs 5.85 weight% (wt%), p < 0.01), in PC (1.02 vs 1.25 w t%, p < 0.05) and in CE (0.25 vs 0.54 wt%, p < 0.05). There was no sig nificant difference of DHA between group B and controls. AA levels wer e similar in phospholipids of all groups. We conclude that reduced lev els of long-chain polyunsaturated fatty acids in PKU patients occur on ly in those patients with strict dietary therapy with respect to n - 3 fatty acids, most probably caused by reduced intake of n - 3 fatty ac ids.