RecruitingOff Treatment Urinary Copper Excretion in Wilson Disease, Pilot StudyThis is a prospective study that will determine the optimal timing for 24-hour urinary copper excretion (UCE) measurement after temporary discontinuation of standard therapies in Wilson Disease (WD) patients. The primary objective is to assess whether off-treatment UCE (OT-UCE) correlates with non-ceruloplasmin-bound copper (NCC) levels, aiming to validate OT-UCE as a surrogate marker for systemic copper bioavailability and disease stability. Stable WD patients will be enrolled, temporarily taken off treatment under close monitoring, and undergo UCE and NCC testing. If OT-UCE is validated, it could serve as a practical biomarker for monitoring WD treatment and stability in clinical practice and future trials.