To test the applicability of titin as a potential pharmacodynamic biomarker in humans, urine samples were assessed using the SOMAscan assay at baseline, day 180, and day 360 from DMD participants treated with AAV9-CK8-μDys5 who participated in the IGNITE DMD clinical trial (NCT03368742). The gene discussed is KRT8; the disease is Duchenne muscular dystrophy.