Urinary titin in myotonic dystrophy type 1

Abstract

AbstractIntroduction/AimsUrinary titin, an easy‐to‐obtain marker, has been investigated in muscular dystrophies, but not in myotonic dystrophy type 1 (DM1). We investigated the role of titin as a biomarker of muscle injury in DM1.MethodsWe compared the urinary titin N‐fragment/creatinine ratio in 29 patients with DM1 vs. 30 healthy controls. We also recorded clinical data such as muscle strength, serum creatine kinase, DM1‐related outcome measures, and the 20‐item DM1‐activ questionnaire. The severity of the disease was graded using the Muscular Impairment Rating Scale (MIRS).ResultsThe titin/creatinine ratio was significantly higher in the urine samples of DM1 patients than of healthy controls (median ± mean absolute deviation [MAD]: 39.313 ± 26.546 vs. 6.768 ± 5.245 pmol/mg creatinine; P < .001), and was related to muscle impairment graded by MIRS (τ = 0.503, P = .038).DiscussionUrinary titin may be a biomarker for DM1. Long‐term follow‐up of DM1 patients is needed to investigate the potential role of titin as a biomarker for disease activity and progression.