Wilson Disease Testing

What Causes Wilson Disease?
Wilson disease is caused by mutations in the ATP7B gene.
This gene makes an enzyme that is involved in copper transport.
When the enzyme is mutated (not working properly) copper accumulates in the liver and brain and becomes toxic.

How Does it Run in Families?
Wilson disease is inherited in an autosomal recessive pattern.
Affected individuals have mutations in both copies of ATP7B
Carriers (mutation in only one copy) do not have symptoms

How Does it Run in Families?
Ww
Ww
ww
Ww
WW

Current US Clinical Testing for Wilson Disease
The University of Chicago
Ambry Genetics
Boston University School of Medicine
Mayo Clinic
Prevention Genetics
Seattle Children’s Hospital
University of Oklahoma Health Sciences Center

www.dnatesting.uchicago.edu

Our Test . . .
Full gene sequencing of coding region of atp7b (21 exons)
Cost: $2025
TAT: 4 - 6 weeks

DNA extraction
Process of getting DNA from a blood, saliva, or other body tissue.
http://learn.genetics.utah.edu/content/labs/extraction/
Process of getting DNA from a blood, saliva, or other body tissue.
http://learn.genetics.utah.edu/content/labs/extraction/

Targeting ATP7B
Need to PCR amplify each exon (21) of ATP7B before sequencing
Ex 1
Ex 2
Ex 3
Ex 4
Ex 5
Ex 6
Ex 7
Ex 8
Ex 9

PCR Amplification
Reproduce only the parts of DNA (exons of ATP7B) that you are interested in.
http://www.youtube.com/watch?v=HMC7c2T8fVk

DNA Sequencing
Reading the DNA code within the ATP7B gene to look for any changes.
Cycle sequencing animation
http://www.youtube.com/watch?v=ezAefHhvecM

Ordering Testing
A physician must order the test
We recommend that a geneticist or genetic counselor be involved in ordering testing
Finding a genetics clinic or GC—
www.genetests.org
www.nsgc.org
They will fill out the appropriate paperwork and arrange for blood sample to be sent to The University of Chicago

Ordering Testing
Test report will be faxed to referring physician
Geneticist/GC can explain results and implications to family
Questions? —Please contact me!
Melissa Dempsey, MS
The University of Chicago
773-834-1606
[e-mail]

Insurance/Billing
The University of Chicago will bill your insurance company or accept payment by check or credit card.
All insurance companies are different, but most of them should cover at least part of the cost of testing.
CPT (Current Procedural Terminology) codes:
Insurance companies use these codes to define the method of testing.
For ATP7B testing: 83891, 83898 x 4, 83904 x 9, 83912 .

Possible Results:
2 mutations detected:
confirms diagnosis of Wilson Disease.
allows for easy testing of other family members, who may want testing.

Possible Results:
1 mutation detected:
does not confirm or rule out Wilson Disease
patient may have 2nd mutation that wasn’t detected
Patient may be a carrier of WD and have some other reason for their symptoms
~1/90 individuals are carriers of WD.

Possible Results:
No mutation detected:
does not rule out the diagnosis.
~98% of people with WD will have mutations identified.
If diagnosis is doubtful, a negative result leans against the diagnosis, and other possible diagnoses should be considered.

Possible Results:
Variant of unknown significance:
A small number of people will have a change in the gene, but we do not know what the change means
May recommend testing other family members to try to figure it out.

Case #1
12 year old female with abnormal copper levels
Exon 6
c.1934T>G (p.M645R)

Case #1
12 year old female with abnormal copper levels
Exon 18
c.3809A>G (p.N1270S)