Receiver operating curve analyses of urinary titin of healthy 3-y-old children may be a noninvasive screening method for Duchenne muscular dystrophy.

ABSTRACT

BACKGROUND: Duchenne muscular dystrophy (DMD) is a progressive, fatal muscle wasting disease. Early detection of DMD by mass screening may enable the early treatment of these patients. We have reported that urinary titin concentration, an indicator of severe muscle wasting, is a diagnostic biomarker for DMD. METHODS: Urinary titin concentrations were measured in healthy 3-y-old children and, by comparison with concentrations in 4 DMD patients, and validated as a screening biomarker for DMD. Urine samples were obtained from 100 healthy Japanese children, 52 boys and 48 girls, and their urinary titin concentrations measured by ELISA. RESULTS: The mean ±â€¯SD urinary titin concentration was 1.5 ±â€¯2.5 nmol/l, and the mean urinary titin concentration normalized to creatinine was 2.2 ±â€¯4.1 pmol/mg creatinine, with no differences between boys and girls. Histograms and box-and-whisker plots showed that almost all titin and normalized titin concentrations were in narrow ranges, with one outlier in common. Receiver operating characteristic curve analysis showed that titin and normalized-titin concentrations from healthy 3-y-olds were completely separate from those of 3-y-old DMD patients. CONCLUSIONS: These findings indicate that urinary titin may be an excellent non-invasive biomarker to screen for DMD.