Early detection of Duchenne muscular dystrophy (DMD) by mass screening may enable the early treatment of these patients. Here, the authors report that urinary titin concentration, an indicator of severe muscle wasting, is a diagnostic biomarker for DMD. Urinary titin concentrations were measured in healthy 3-year-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. Receiver operating characteristic curve analysis showed that titin and normalized-titin concentrations from healthy 3-year-olds were completely separate from those of 3-year-old DMD patients. These findings suggest that urinary titin may be an excellent non-invasive biomarker to screen for DMD.
