Diagnosis and Testing
How does someone get tested for Clouston Syndrome?
Genetic testing for Clouston syndrome can be ordered by a geneticist or genetic counselor. At your appointment, you will talk about your medical history and about your family members and their medical concerns. The doctor will do a physical examination. You will get information about testing and if you decide you want genetic testing, you can give consent (permission). This might happen in one visit, or over a few visits.
Each clinic works differently and sometimes the clinic checks with your insurance about coverage for testing, but it could also be your responsibility. If you choose to do genetic testing, a blood sample and signed paperwork is sent to a laboratory. Your results are sent back to the geneticist and genetic counselor and they will contact you with results.
More Diagnosis and Testing Content
Is there newborn testing for Clouston Syndrome?
Each state has a newborn screen which includes a group of genetic conditions. Clouston syndrome is not included in any newborn screens in the United States. If there is a family history of Clouston syndrome or if Clouston syndrome is suspected at birth, genetic testing can be ordered. This testing is usually performed on a blood sample either collected from the umbilical cord or from a normal blood draw.
Is there more than one test for Clouston Syndrome?
As of 2019, only the GJB6 gene is known to be associated with Clouston syndrome. Genetic testing involves looking at this gene for specific changes. There are four GJB6 gene mutations to most commonly cause Clouston syndrome.
Imagine that the GJB6 gene is a long sentence. This sentence tells the body how to grow and develop. One type of genetic testing is called sequencing. Sequencing looks for spelling errors in this sentence. It can find a letter that is in the wrong place. Another type of genetic testing is called deletion/duplication testing. Deletion/duplication testing looks for larger pieces of missing (deleted) or extra (duplicated) information, like words in the sentence.
If the sentence has spelling errors or missing/extra words, it might not make sense. The body then grows and develops differently. The result is a genetic condition.
The first genetic test that should be done will look for the four specific GJB6 mutations known to be associated with Clouston syndrome. If this testing is unrevealing, sequencing of the whole GJB6 gene should be done. Deletion/duplication testing is usually not offered for Clouston syndrome because no mutations are known to be picked up through this analysis.
If there is a known GJB6 gene mutation in the family, testing can specifically look for this mutation in other family members. This is called site-specific analysis.
Some labs offer ectodermal dysplasia panels that look at many different genes at once. These panels might include the GJB6 gene.
A medical geneticist or genetic counselor can help you understand more about the testing process. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website . Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Who else in my family should I test for Clouston Syndrome?
Genetic testing can be offered to other family members if a GJB6 gene mutation is found in an affected person. For example, if a child is found to have a GJB6 gene mutation, testing should first be offered to the child's parents. If the mother or father is found to have the same GJB6 gene mutation, testing can then be offered to the parent's other children, siblings, and parents.
This is a dominant condition. Most people with Clouston syndrome will often have a parent with the same genetic mutation. However, in some cases the genetic mutation happens for the first time in that baby. In those cases, the parents will not have the same genetic mutation.
It can be helpful to meet with a geneticist and/or a genetic counselor to discuss risks to other family members and to find out who can be tested. Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Does it matter what type of sample you test for Clouston Syndrome?
Genetic testing for Clouston syndrome typically involves a blood sample but some laboratories accept saliva samples. Skin or muscle samples taken via biopsy are not usually used for genetic testing to diagnose Clouston syndrome.
If a mother or father is affected with Clouston Syndrome, is there testing that can be performed during the pregnancy to see if their baby is affected?
If a parent has Clouston syndrome and a known GJB6 gene mutation, genetic testing can be done during a pregnancy. Chorionic villus sampling (CVS) and amniocentesis are procedures that can be done during a pregnancy. These procedures are invasive and can pose a small risk for miscarriage or loss of the pregnancy.
CVS involves removing a small piece of the placenta and sending it to a laboratory for genetic testing. CVS can be performed around 10-12 weeks of gestation.
Amniocentesis involves taking a sample of amniotic fluid and sending that sample to a laboratory for genetic testing. This testing can be performed starting at 15 weeks of gestation.
Testing will look for the same GJB6 gene mutation found in the parent. Testing cannot predict the baby's clinical features.
If you are interested in prenatal testing for Clouston syndrome, you can speak with a genetic counselor in your area. Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Can I make sure my baby won't be affected with Clouston syndrome before I become pregnant?
Yes. There is a technology called preimplantation genetic diagnosis (PGD) that may be available if the family has a known GJB6 gene mutation.
Embryos are made in a laboratory using the mother's egg cells and the father's sperm cells. Genetic testing can then be done to see if the GJB6 gene mutation is present. Embryos that don't have the GJB6 gene mutation can then be implanted in the mother.
If you are interested in preimplantation genetic diagnosis, you can speak with a genetic counselor who specializes in assisted reproductive technology. Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.