Background: Ubiquinone-10 is a lipid with important metabolic functions tha
t may be decreased in phenylketonuria (PKU) because patients with PKU consu
me diets restricted in natural proteins.
Objective: We studied serum ubiquinone-10 concentrations in PKU patients.
Design: This was a retrospective, transversal study in which we compared se
rum ubiquinone-10, plasma cholesterol, plasma tyrosine, and plasma phenylal
anine concentrations in 43 PKU patients with concentrations in a reference
population (n = 102). Serum ubiquinone-10 concentrations were analyzed by H
PLC with ultraviolet detection. Plasma tyrosine and phenylalanine were meas
ured by ion-exchange chromatography.
Results: Serum ubiquinone-10 concentrations in PKU patients were significan
tly lower than in the reference population (P < 0.01 for patients aged 1 mo
to <8 y and P < 0.00005 for patients aged 8-33 y). Moreover, 5 of 18 PKU p
atients (28%) in the younger age group and 10 of 23 (43%) in the older age
group had serum ubiquinone-10 concentrations below the reference interval.
Conclusions: Serum ubiquinone-10 deficiency appears to be related to the re
stricted diet of PKU patients. Because serum ubiquinone-10 plays a major an
tioxidant role in the protection of circulating lipoproteins, the correctio
n of ubiquinone-10 concentrations should be considered in PKU patients. Fur
ther investigation seems advisable to elucidate whether the deficiency in s
erum ubiquinone-10 status is clinically significant.