HEMOSTATIC VARIABLES IN PHENYLKETONURIC CHILDREN UNDER DIETARY-TREATMENT

Classical phenylketonuria (PKU) (McKusick 261600) is an inborn error o f metabolism treated by a controlled low-phenylalanine (Phe) diet star ted as soon as possible in the first days of life. Such a diet can be achieved with vegetable protein and can be considered non-atherogenic because of the reduction of animal products. Thirty patients with PKU were classified into two groups according to their annual mean Phe lev els. Their daily protein intake was largely replaced by PKU2 Milupa wh ich contains a mixture of amino acids. The product has no phenylalanin e or fat of any kind. Thirty-eight (38) individuals of comparable age were used as controls. Group A (n = 15) had good compliance with the s pecial diet (Phe mean 192 +/- 115 mu mol/L); group B (n = 15) did not strictly adhere to the diet (Phe mean 595 +/- 263 mu mol/L). Certain h aemostatic components (factors I, VII, VIII, and X, antithrombin III, protein C, and plasminogen) and lipid variables (cholesterol, triglyce rides, high-density lipoprotein, low-density lipoprotein, very-low-den sity lipoprotein) as well as Phe levels were estimated. All the haemos tatic factors studied were found within the normal range with the exce ption of a significant reduction in protein C in both groups of PKU pa tients. Furthermore, a statistically significant reduction in factor V II and X concentrations was observed in patients on strict diet. Chole sterol and low-density lipoprotein concentrations were significantly l ower in PKU children compared to normal controls. It is suggested that even though the special diet of PKU children, especially in group A, is rich in vegetables, the reduced fat intake might have impaired the absorption of vitamin K and its delivery to the site of synthesis of v itamin K-dependent haemostatic factors.