X-LINKED CARRIER
The relevant test for women before planning a pregnancy.
X-LINKED CARRIER
A female carrier of an X-linked condition has a 50% risk of passing the disorder on to a boy-child.
Highlights
- The X-linked carrier test is performed using two techniques: Next Generation Sequencing (NGS) and CGG Repeat Expansion with TP-PCR.
- The test studies 12 genes related to recessive diseases specifically associated with the X chromosome.
- X-Linked Carrier is recommended only for women before planning a pregnancy
X-Linked Carrier
The X-Linked Carrier test is a specific genetic test for women who wants to get pregnant. It is a genetic screening panel containing 12 genes associated with recessive diseases associated specifically with the X chromosome. The X-Linked Carrier test reveals if the female is a carrier of these genetic diseases and thereby if she risks passing them on to her children. As boys only have one X chromosome which they inherit from the mother the X-linked disorders are more prominent in boys.
Why is this X-linked carrier test relevant for women?
This test is designed specifically for women because only women can carry a mutation on the X chromosome without suffering from the disease. This is because:
- Women have two XX chromosomes:
Since women have two X-chromosomes, they can be unaffected carriers. If the mother transmits a mutated X-chromosome to a daughter the daughter will have a healthy X-chromosome from the father’s side and will become a carrier like her mother. A girl is unlikely to have a disease-causing mutation on both X chromosomes since the father would have revealed (or suffered from) the disorder if he carries a mutated X-chromosome.
- Men have an X and a Y chromosome:
Since boys get a Y-chromosome from the father’s side, they only have the X-chromosome transmitted from the mother and the disorder will appear if the mother transmits the mutated X-chromosome. This is why X-linked disorders are more prominent in boys.
What are the diseases related to the X-linked carrier test?
- Fragile X Syndrome.
- Adrenoleukodystrophy.
- Choroideremia.
- Alport syndrome.
- Duchenne muscular dystrophy (DMD).
- Hypohidrotic ectodermal dysplasia.
- Hemophilia A (HEMA).
- Hemophilia B (HEMB).
- Emery-Dreifuss muscular dystrophy 6.
- Fabry disease.
- Retinoschisis1, X-linked, juvenile (RS1).
How to do the test?
To do the test, a sample of saliva or blood is necessary. To collect the saliva sample, we will send a sample collection kit with instructions for collecting the sample, and shipping instructions for sending the sample to Amplexa Genetics.
You can expect a response no later than four weeks after we have received your sample.
THE ANALYSIS
Technical Specifications
- The panel includes 12 X-linked genes
- Sequencing of coding regions +/- 10 flanking intronic bases
- ≥99% of targeted genes covered at ≥20x sequenced by Next Generation Sequencing
- FMR1 is analyzed for CGG repeats expansion with TP-PCR
- All low-quality SNV’s are verified by Sanger Sequencing
SAMPLE REQUIREMENTS
- Blood (2-5 ml EDTA-blood),
- Saliva sample in preservation solution (minimum 2 mL) or
- DNA (minimum 3 µg)
To learn more about how X-Linked Carrier test can help your patients, please contact one of our experts for more information.
