How is Saethre-Chotzen inherited?
Saethre-Chotzen syndrome is inherited in an autosomal dominant pattern. In an autosomal dominant condition, one of an individual’s two copies of a gene has a change in it that makes it work improperly. This gene change causes the disease.
The gene that is changed in the cause of Saethre-Chotzen syndrome is called TWIST1. In a person with Saethre-Chotzen syndrome, every cell in the body has one broken copy of this gene, and one working copy.
A person who has an autosomal dominant condition like Saethre-Chotzen syndrome has a 50% chance of having a child who also has Saethre-Chotzen syndrome. The risk for somebody to inherit Saethre-Chotzen syndrome is the same no matter if they are a boy or a girl. To learn more about how Saethre-Chotzen syndrome is inherited, speak with your genetic counselor.
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What does it mean to have inherited a "variant of uncertain significance" in the gene for Saethre-Chotzen Syndrome?
There are some gene changes that labs are certain cause a disease, and some gene changes that labs are certain do not cause a disease. A "variant of uncertain significance" is a gene change that may or may not cause a disease. The lab is uncertain at this time what the change means, and needs to do more research and look at many more genes to determine if this is a disease-causing change or not. In regards to Saethre-Chotzen, if a person is found to have a "variant of uncertain significance" in the TWIST1 gene, the lab is not sure if this person has Saethre-Chotzen Syndrome or not. That child may have a clinical diagnosis of Saethre-Chotzen, given by a doctor, without having a genetic diagnosis based on a definite positive test result. If you have a "variant of uncertain significance" in the TWIST1 gene, speak with your doctor or genetic counselor.
Are there forms of Saethre-Chotzen Syndrome that aren’t genetic?
Most individuals with Saethre-Chotzen syndrome have it due to a small change in one copy of the TWIST1 gene in the cells that make up their bodies. Occasionally, this gene is completely deleted, which also causes Saethre-Chotzen.
Some individuals have Saethre-Chotzen based on their symptoms, but do not have a change in the TWIST1 gene that can be detected by current technologies. A doctor can help confirm a diagnosis of Saethre-Chotzen syndrome in an individual.
Is there any way to prevent my future children from having Saethre-Chotzen?
If a genetic change is identified in your child, you and your partner can have genetic testing to determine if one of you also carries the genetic change. If neither of you carry the same change, it is likely that this is a new change in your child with Saethre-Chotzen syndrome. In this case, there is only a 1% or less chance that your future children could have this disease.
If you or your partner also has the genetic change that causes Saethre-Chotzen syndrome, a technique called Preimplantation Genetic Diagnosis, or PGD, may be an option for your future pregnancies. This is a form of in vitro fertilization (IVF) in which embryos are created outside the mother’s body and tested for the genetic change before they are put into her uterus. This can be a very expensive procedure, however, and you may need to check with your insurance about whether or not it would be covered.
One more option is to get pregnant naturally (without any assistive technologies like IVF and PGD), and have testing during your pregnancy to determine if the baby has the same genetic change that causes Saethre-Chotzen syndrome. Once you know this information, you and your partner may decide whether or not to continue a pregnancy that has the genetic change. A genetic counselor can be helpful in discussing the various options for having a child without Saethre-Chotzen syndrome. To find a genetic counselor, visit: http://nsgc.org/