Low Serum Cholesterol Concentration in Adult Patients with Phenylketonuria- One Centre Experience

Karolina M Stepien1 and Chr

Abstract

Introduction: Phenyloketonuria is a rare metabolic disorder caused by a deficiency of the phenylalanine (Phe) hydroxylase enzyme. A reduced intake of natural proteins helps optimise plasma Phe concentration. A relationship between high plasma Phe level and the inhibition of cholesterol synthesis was previously observed but the mechanisms are unclear. Low LDL-cholesterol concentrations were observed in children and adolescent PKU patients, but not in adults. This is the first paper to present lipid profile in adult patients with this condition. Methods: Lipid profile was analysed in adult patients with PKU. We examined associations between Phe and four outcomes: total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides. Confounding factors (predictors) were taken into account: body mass index (BMI), age and gender. The statistical analysis was performed using multiple linear regression. Results: Among 176 adult patients 91 were females (52%). The mean age was 32 ± 10.7 years. 82 patients (46%) were on strict PKU diet. Mean Phe was 1017 ± 440 μmol/L. Mean total cholesterol was 4.33 ± 0.94 mmol/L, LDL-cholesterol 2.48 ± 0.8 mmol/L, HDL-cholesterol 1.2 ± 0.34 mmol/L, triglycerides 1.6 ± 0.9 mmol/L. There was no correlation between Phe concentration and lipid profile in our cohort of adult patients with PKU. No cardiovascular events were documented in our cohort. Conclusions: In conclusion, the outcomes of the study demonstrate that mean total cholesterol, LDL-cholesterol and triglycerides concentrations were substantially lower as compared to healthy population, which may confer their reduced cardiovascular risk. Lipid profile remained low irrespectively of Phe concentration.

Relevant Publications in Clinical & Medical Biochemistry