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Haemostatic variables in phenylketonuric children under dietary treatment
K H Schulpis1, H Platokouki, E D Papakonstantinou
1Institute of Child Health, "Aghia Sophia' Children's Hospital, Athens, Greece.
Insights
Phenylketonuria (PKU) patients on low-phenylalanine diets showed reduced protein C, factor VII, and X. Low-fat PKU diets may impair vitamin K absorption, affecting blood clotting factors.
Area of Science:
- Metabolic disorders
- Nutritional science
- Hematology
Background:
- Classical phenylketonuria (PKU) is an inherited metabolic disorder requiring early dietary intervention.
- Low-phenylalanine (Phe) diets, often vegetable-based, are crucial for managing PKU.
- These diets aim to prevent neurological damage by limiting Phe intake.
Purpose of the Study:
- To investigate the impact of strict low-Phe diets on hemostatic components and lipid profiles in PKU patients.
- To compare these parameters between PKU patients with good and poor dietary compliance and healthy controls.
Main Methods:
- Thirty PKU patients were divided into two groups based on dietary adherence (good vs. poor).
- Hemostatic factors (I, VII, VIII, X, antithrombin III, protein C, plasminogen) and lipid variables were measured.
- A control group of 38 age-matched individuals was included for comparison.
Main Results:
- PKU patients exhibited significantly lower cholesterol and low-density lipoprotein (LDL) levels compared to controls.
- A significant reduction in protein C was observed in both PKU groups.
- Patients with strict dietary adherence showed further reductions in factors VII and X.
Conclusions:
- Strict low-Phe diets in PKU patients may lead to reduced levels of certain vitamin K-dependent clotting factors.
- Reduced fat intake associated with these diets could impair vitamin K absorption.
- Further research is needed to optimize PKU diets for both metabolic control and hemostatic health.
Abstract:
Classical phenylketonuria (PKU) (McKusick 261600) is an inborn error of metabolism treated by a controlled low-phenylalanine (Phe) diet started 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 levels. Their daily protein intake was largely replaced by PKU2 Milupa which contains a mixture of amino acids. The product has no phenylalanine 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 special diet (Phe mean 192 +/- 115 mumol/L); group B (n = 15) did not strictly adhere to the diet (Phe mean 595 +/- 263 mumol/L). Certain haemostatic components (factors I, VII, VIII, and X, antithrombin III, protein C, and plasminogen) and lipid variables (cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very-low-density lipoprotein) as well as Phe levels were estimated. All the haemostatic factors studied were found within the normal range with the exception of a significant reduction in protein C in both groups of PKU patients. Furthermore, a statistically significant reduction in factor VII and X concentrations was observed in patients on strict diet. Cholesterol and low-density lipoprotein concentrations were significantly lower 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 vitamin K-dependent haemostatic factors.