As a noninvasive biomarker, urine titin fragment levels have been used in DMD patients and animal model16–21 and its fragments are also detected in patients with Becker muscular dystrophy, Limb-girdle muscular dystrophy, Fukuyama congenital muscular dystrophy, and myotonic dystrophy type 1 but not in neurogenic spinal muscular atrophy16,22,23. This evidence concerns the gene TTN and Duchenne muscular dystrophy.