Test
The goals of testing are to diagnose Wilson’s 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.
Testing is also used to identify family members who are pre-symptomatic or carriers and sometimes for prenatal evaluation.
Laboratory Tests
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’s disease but are pre-symptomatic. Other liver diseases may also result in excess copper storage and increased copper in the blood. Acute cases of Wilson’s disease may be difficult to distinguish from other forms of liver disease. Testing may include:
- Caeruloplasmin– requested to help diagnose Wilson’s disease. Its level is usually decreased but about 5% of patients with Wilson’s disease who have neurological symptoms will have normal caeruloplasmin levels as will up to 40% of those with liver symptoms.
- Total serum copper – may be requested to help diagnose. Its level is usually decreased in Wilson’s disease.
- Free serum copper (non-caeruloplasmin-bound) – used to diagnose and monitor, usually increased in Wilson’s disease.
- 24-hour urine copper – used to diagnose and monitor, usually increased I Wilson’s disease.
- Liver copper – a liver tissue biopsy collected to help diagnose. Its level is usually increased in Wilson’s disease but deposits of copper may not be evenly distributed in the liver and so the test may occasionally be negative in patients with the disease.
- 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’s disease and identify mutations and 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. The severity and course of the disease can vary significantly, even between family members with the same mutations. The ATP7B gene mutations most prevalent in a region or ethnic population may be found. If the mutations have been identified in a patient with Wilson’s disease then the family members can be tested for these. Gene sequencing can be performed to examine the entire gene for mutations. This is the most thorough test. Linkage analysis can also be carried out. This requires blood from parents, siblings, and an affected family member. It compares genetic information which is present close to the ATP7B gene.
Other tests may be performed to evaluate organ function and blood cell status, including:
- FBC (Full Blood Count)
- Liver function tests (LFTs)
Non-Laboratory Tests
- Eye exam – slit lamp examination for Kayser-Fleischer rings in the cornea
- MRI (magnetic resonance imaging) scan
- CT (computerized tomography) scan