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Test ID: WDZ Wilson Disease, Full Gene Analysis

Useful For

Diagnostic confirmation of Wilson disease

Testing Algorithm

See Wilson Disease Testing Algorithm in Special Instructions.

Method Name

Polymerase Chain Reaction (PCR)/DNA Sequencing

Reporting Name

Wilson Disease Full Gene Analysis

Specimen Type

Varies


Shipping Instructions


Specimen preferred to arrive within 96 hours of draw.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories for instructions for testing patients who have received a bone marrow transplant.

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Clinical Information

Wilson disease (WD) is an autosomal recessive disorder that results from the body's inability to excrete excess copper. Typically, the liver releases excess copper into the bile. Individuals with WD lack the necessary enzyme that facilitates clearance of copper from the liver to bile. As a result, copper accumulates first in the liver and gradually in other organs. The brain, kidneys, bones, and corneas can also be affected. WD affects approximately 1 in 30,000 people worldwide, with a carrier frequency of approximately 1 in 90 individuals.

 

The primary clinical manifestations of WD are hepatic and neurologic. Hepatic disease can be quite variable, ranging from hepatomegaly or other nonspecific symptoms that mimic viral hepatitis to severe liver damage, such as cirrhosis. Neurologic symptoms of WD can include poor fine-motor coordination, ataxia, and dysphagia. Psychiatric manifestations are reported in approximately 20% of individuals with WD. A characteristic ophthalmologic finding is the Kayser-Fleischer ring. Individuals with WD typically begin to show symptoms of liver dysfunction or neurologic disease in the first or second decade of life. If not treated, WD can cause liver failure, severe brain damage, and even death.

 

A variety of laboratory tests are recommended in the initial evaluation for WD. In approximately 95% of cases, serum ceruloplasmin is below normal. Additionally, patients with WD show decreased copper in serum, increased copper in urine, and significantly elevated copper on liver biopsy. While liver biopsy is not recommended as a first-tier screening test for WD, it can be useful to help interpret discrepant biochemical or molecular results. The other tests should be performed prior to sequence analysis of the ATP7B gene, the gene responsible for WD. More than 300 disease-causing mutations have been identified in the ATP7B gene. Most mutations are family-specific with the exception of the H1069Q mutation, which accounts for >50% of identified disease alleles in the Northern European Caucasian population.

 

See Wilson Disease Testing Algorithm in Special Instructions for additional information.

Reference Values

An interpretive report will be provided.

Interpretation

All detected alterations are evaluated according to American College of Medical Genetics recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Clinical Reference

1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 2015 May;17(5):405-424

2. Roberts EA, Schilsky ML, American Association for Study of Liver Diseases (AASLD): Diagnosis and treatment of Wilson disease: an update. Hepatology 2008;47(6):2089-2111

3. Mak CM, Lam CW: Diagnosis of Wilson's disease: a comprehensive review. Crit Rev Clin Lab Sci 2008;45(3):263-290

Day(s) and Time(s) Performed

Performed weekly; Varies

Analytic Time

14 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81406-ATP7B (ATPase, Cu++ transporting, beta polypeptide) (eg, Wilson disease), full gene sequence

LOINC Code Information

Test ID Test Order Name Order LOINC Value
WDZ Wilson Disease Full Gene Analysis In Process

 

Result ID Test Result Name Result LOINC Value
54048 Result Summary 50397-9
54049 Result In Process
54050 Interpretation In Process
54051 Additional Information 48767-8
54052 Specimen 31208-2
54053 Source 31208-2
54054 Released By No LOINC Needed

Forms

1. Molecular Genetics: Congenital Inherited Diseases Patient Information (T521) in Special Instructions

2. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

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