- Hello!
I am a member of the GenomeConnect and ClinGen Patient Data Sharing Program Team.
In this video, we will walk through an example genetic test report with a copy number variant
together.
We won t go through all of the terms you might see on your own genetic test report in this
video, but many of these other terms are covered in our other videos.
- Many of you listening have gone through the genetic testing process and might have
spoken to a genetic counselor or a geneticist, so some of what we review might be familiar.
Our hope is to break down some of the terms and information today.
- On the screen is an example report we will walk through.
This example report has a genetic change or copy number variant.
First, we will briefly touch on what a microarray test can detect and what a copy number variant
is, before going over this example report.
- A microarray looks at all of an individual s chromosomes.
This test will tell us if a person has the typical number of chromosomes, which is 46,
or if they have any missing or extra copies of their chromosomes.
When a full chromosome is missing, it s called monosomy and when there is a full extra chromosome
present, it s called trisomy.
- This test also can detect when there are missing or extra pieces within our chromosomes.
When there are missing pieces, it is sometimes called a deletion, and when there are extra
pieces, it can be called a duplication.
- Copy number variants refers to deletions and duplications of our chromosomes as described
in the last slide.
- You may see negative/normal on the genetic test report if there were no copy number changes
detected.
However, in this example report it reads, positive for a heterozygous 2.69 Mb deletion
at 22q11.2.
Positive means there was a difference detected in the chromosomes.
Heterozygous means the difference was found within one of the chromosomes, not on both.
The number 2.69 is the size of the deletion.
22q11.2 is the specific location of the deletion on chromosome 22.
- Copy number variants are typically named based on their location in the chromosomes,
as in our example report.
You may see the term p-arm and q-arm on this slide with an arrowing pointing to the chromosomes.
Each chromosome usually has two sections with a divider in between the two sections.
These two sections are called the p-arm and q-arm.
P stands for petite because it is the smaller of the two sections, and Q stands for queue
meaning tail and is the longer section of the chromosome.
- Using our example report, 22q11.21 deletion, this is named after the specific part of chromosome
22 that is missing.
A piece of the long arm, or q-arm has been deleted.
If you look at the chromosome, they have a banding or striped pattern.
This is actually what they look like under the microscope.
The 11.21 of 22q11.21 tells exactly what band or stripe of the chromosome has the deletion.
- On the report you will likely see the classification of the copy number variant.
In this example report the classification is pathogenic, meaning this specific deletion
is thought to be associated with health or developmental differences.
- To learn more about other types of variant classification you can listen to our other
videos that cover this topic.
- Somewhere on the report, will be a results and interpretation section.
This section will give information about the specific copy number change may show.
It may also go over the genes within the region of the chromosome that are impacted or symptoms
an individual may show.
- This section sometimes discusses testing of family members to understand if another
individual in the family has the same variant and whether it was inherited from a parent.
- Thank you for watching our how to read your array report video!
If you have general questions about this topic or other genetics-related topics, you can
reach us at info@genomeconnect.org or by calling 570-214-1721 or toll free 855-322-7683
- If you have questions about your genetic test results, we encourage you to reach out
to your doctor or genetic counselor.
- We hope you join us for our other videos!