Systemic oxidative stress, as measured by urinary allantoin and F(2)-isoprostanes, is not increased in Down syndrome.

<bold>Purpose: </bold>Oxidative stress has been implicated in Down syndrome (DS) pathology. This study compares DS individuals and controls on their urinary levels of allantoin and 2,3-dinor-iPF2α-III; these biomarkers have been previously validated in a clinical model of oxidative stress.<bold>Methods: </bold>Urine samples were collected from 48 individuals with DS and 130 controls. Biomarkers were assayed by ultraperformance liquid chromatography-tandem mass spectrometry, normalized by urinary creatinine concentration.<bold>Results: </bold>After adjusting for age and gender, mean allantoin levels were lower among DS individuals versus controls (P = .04). The adjusted mean levels of 2,3-dinor-iPF2α-III were similar in DS individuals and controls (P = .7).<bold>Conclusions: </bold>Our results do not support the hypothesis that DS individuals have chronic systemic oxidative stress. [ABSTRACT FROM AUTHOR]