The goals with testing are to diagnose Wilson disease, evaluate its severity, distinguish between those who have the disease and those who are carriers, rule out other causes of liver and neurological dysfunction, and to monitor the effectiveness of treatment for Wilson disease. Testing is also used to identify family members who are presymptomatic or carriers, and sometimes for prenatal evaluation.
Biochemical testing – Care must be taken to avoid external copper contamination in sample collection. Repeat testing of abnormal results may be recommended. Test results of people who are carriers may overlap with those who have Wilson disease but are presymptomatic. Other diseases may also result in excess copper storage and increased copper in the blood. Acute cases of Wilson disease may be difficult to distinguish from other forms of hepatitis. Testing may include:
- Ceruloplasmin – ordered to help diagnose Wilson disease; usually decreased, but about 5% of affected patients who have neurological symptoms will have normal ceruloplasmin levels as will up to 40% of those with hepatic symptoms.
- Total serum copper – may be ordered to help diagnose; usually decreased.
- Free serum copper (non-ceruloplasmin-bound) – used to diagnose and monitor; usually increased.
- 24-hour urine copper – used to diagnose and monitor; usually increased.
- Hepatic copper – a liver tissue biopsy collected to help diagnose; deposits of copper may not be evenly distributed in the liver.
Molecular genetic testing – This is specialized testing that is available from a limited number of reference or research laboratories. It is used to diagnose Wilson disease and identify mutation(s) and identify carriers. Some prediction of disease severity can be established based upon the mutations present, but testing cannot determine the severity, complications, or organ involvement that will be experienced by a specific individual. Severity can vary significantly, even between family members with the same mutations.
- ATP7B gene: Panels of the most prevalent mutations in a region or ethnic population may be performed.
- If the mutations have been identified in a person with Wilson disease, then the family members of that person can be tested for those specific mutations.
- Gene sequencing can be performed to examine the entire gene for mutations. This is the most thorough test.
- Linkage analysis: This requires blood from parents, siblings, and an affected family member. It compares genetic information present close to the ATP7B gene.
Other tests may be performed to evaluate organ function and blood cell status, including:
- Eye exam (slit lamp for Kayser-Fleischer rings in the cornea)
- Clinical examination and personal and family history
- Magnetic resonance imaging (MRI) scan
- Computerized tomography (CT) scan