Off Treatment Urinary Copper Excretion in Wilson Disease, Pilot Study

Inclusion Criteria: * Patients with Wilson Disease as defined by Leipzig score ≥4. * Provision of signed and dated informed consent form. * Stated willingness to comply with all study procedures (serial 24 h urine collections and local collection of samples for NCC, liver function and estimated GFR) and availability for the duration of the study. * Treated WD for at least 12 months prior to study entry. * Aminotransferase values (ASAT and ALAT) \< 2 times the upper limit of normal (ULN). * INR \< 1.5 or stable INR for those with initial elevated INR for at least six months prior to study entry in the absence of anticoagulation therapy. * Renal function defined as eGFR \> 30 cc/min. * No change of WD therapy during the previous 6 months of study enrollment. Exclusion Criteria: * Current dual / mixed therapy for WD (i.e. zinc and d-penicillamine or trientine at the same time) * Current Pregnancy or lactation. \* * Recent estrogen-based treatment (in the last month). * Cirrhosis with recent hepatic decompensation (within the last 6 months) - new onset of ascites, spontaneous bacterial peritonitis, esophageal variceal bleeding, or hepatic encephalopathy * Investigator believes the patient will be unable to do the required 24-hour urine studies and participate in the follow up visits as expected. * Previous non-compliance for therapy and/or to low-copper diet that would compromise the evaluation of previous UCE and/ or results from the off-treatment period. * Childbearing ag…