The primary objective of the study is to determine the relevance and appropriateness of outcome assessments, including biomarkers, within the Wilson disease population to inform study design and endpoint selection for future clinical studies.

Given the limited information on the frequency and spectrum of disease manifestations and clinical course of Wilson disease, the UX701-CL001 study aims to assess the utility and feasibility of various assessments and biomarkers to inform endpoint selection for future clinical studies, better understand the relationship between biomarkers and potential clinical outcomes, and characterize the clinical presentation of Wilson disease. UX701-CL001 is a clinical survey study. Subjects will complete assessments at the study site and at home to evaluate the clinical manifestations of Wilson disease in clinical and real-world environments.

Inclusion Criteria:

1. Male or female ≥ 12 years of age at the time written informed consent is provided.
2. Confirmed diagnosis of Wilson disease.
3. Have a documented history of copper chelator (ie, penicillamine, trientine) and/or zinc therapy or be ≥ 1 year post liver transplant with no active associated complications.
4. Willing and able to comply with all study procedures and requirements. If < 18 years of age (or as required by region), have a caregiver who is willing and able to assist with study requirements if needed.
5. Willing and able to provide written informed consent after the study has been explained and before any study-related data are collected or study-related procedures are performed. If < 18 years of age (or as required by region), willing and able to provide written assent and have a legally authorized representative who is willing and able to provide written informed consent after the study has been explained and before any study-related data are collected or study-related procedures are performed.

Exclusion Criteria:

1. History of liver disease due to a medical condition unrelated to Wilson disease.
2. Liver fibrosis stage F3 or F4.
3. Decompensated hepatic cirrhosis and/or evidence of portal hypertension.
4. Marked neurological disease requiring either nasogastric feeding or intensive inpatient medical care.
5. Female subject who is pregnant or breastfeeding or who plans to become pregnant at any time during the study.
6. Female subject of childbearing potential who has a positive urine pregnancy test on Day 1 or is unwilling to have additional pregnancy tests during the study.
7. Current or previous participation in a gene transfer study.
8. Presence or history of any disease or condition that, in the Investigator's opinion, would interfere with the subject's safety or ability to participate in the study or significantly affect interpretation of study results.

Subjects with a confirmed diagnosis of Wilson Disease will be enrolled from outpatient clinics and metabolic genetic centers in the United States. Subjects may participate regardless of their current treatment. Subjects who have had a liver transplant for treatment of Wilson Disease are also invited to participate.