Being informed about the genetics of dystonia can be important in the diagnosis and treatment process.
Individuals with dystonia may be concerned that their children are at risk of inheriting the disorder. There are forms of dystonia that are known to be genetic and forms that may or may not have a genetic component—researchers cannot confirm or rule it out at this time. Numerous genes have been linked to dystonia.
Click here for an update on dystonia genetics from the Dystonia Dialogue (USA) newsletter
A genetic counselor can help individuals and families learn about the genetics of dystonia and whether they are eligible for genetic testing. Researchers are actively seeking to better understand the genetics of all dystonia's and to identify dystonia-causing genes.
Click here for an article about genetic counseling from the Dystonia Dialogue (USA) newsletter.
Novel sophisticated research tools are providing investigators new ways to explore the genetics of dystonia. For more information about discovery through DNA, click here.
Click here to watch the 'Dystonia Genetics & Genetic Testing' Video - by the DMRF USA. Please note that some information/resources in this video may not be relevant to those residing in Canada.
- What Forms of Dystonia are Genetic?
If an individual has a form of dystonia that is known to be genetic then there is a chance that the person may pass the disorder on to his/her biological children. This is especially true if other family members exhibit symptoms or are already diagnosed.
Genetic dystonias that are known to run in families can include early onset dystonias, isolated (primary) cervical dystonia, dopa-responsive dystonias, myoclonus-dystonia, paroxysmal dystonia's/dyskinesias, rapid-onset dystonia-parkinsonism, X-linked dystonia-parkinsonism, and others.
However, not everyone who inherits a dystonia-causing gene will develop symptoms. Also, some people develop dystonia due to a genetic mutation without any apparent family history. And to complicate things further, there are families in which many members are diagnosed with dystonia but no specific genetic mutation has yet been identified.
Scientists are actively seeking additional dystonia genes. Studying the genetics of dystonia will not only help refine diagnostic and reproductive technology applications, but it also contributes greatly to our understanding of dystonia and quest for better treatments and a cure. For more information on genes are proteins linked with dystonia, click here.
- Inheritance Patterns
One of the greatest mysteries that dystonia researchers are working to solve is the fact that not everyone who inherits a dystonia-causing gene will develop symptoms.
Most of the dystonias for which genes have been identified are dominantly inherited, meaning that only one parent needs to have the gene for a child to inherit the disorder. However, most dystonia genes also exhibit reduced penetrance, which means that not every person who inherits the gene will develop symptoms.
Scientists are actively seeking additional dystonia genes. Studying the genetics of dystonia will not only help refine diagnostic and reproductive health applications, but also contributes greatly to our understanding of dystonia and quest for better treatments and a cure.
- Acquired Dystonia
If an individual’s dystonia is secondary to an injury to the brain or nervous system (including exposure to certain medications or stroke), his/her children may not necessarily be at increased risk of developing dystonia. However, researchers do not know at this time whether individuals who develop acquired dystonia's have a genetic predisposition that makes them vulnerable to dystonia. It could also be that individuals who do not develop dystonia, despite injuries to the nervous system known to cause symptoms in some cases, have a protective factor that is lacking in those individuals who do develop secondary dystonia's. Moreover, dystonia can occur as a symptom of various genetically-caused diseases, in which the inheritance patterns vary.
- Family Planning: In Vitro Fertilization & Preimplantation Genetic Testing
Some families with specific inherited types of dystonia have used in vitro fertilization (IVF) and pre-implantation genetic testing (PGT) to essentially eliminate the risk of future generations being born with dystonia-causing gene mutations. You can read more about genetic testing and screening from the Government of Canada here.
- What is In Vitro Fertilization?
In vitro fertilization (IVF) is a method of assisted reproduction that involves combining an egg with sperm in a laboratory. If the egg fertilizes and begins cell division, the resulting embryo is transferred to the uterus where it will hopefully implant in the uterine lining and develop into a successful pregnancy.
- What is Preimplantation Genetic Testing?
Preimplantation genetic testing (PGT) is a group of techniques to examine embryos during in vitro fertilization (IVF) for a range of genetic problems before possible transfer to the uterus.
These genetic defects include single gene disorders (for example, DYT1-dystonia), a missing or extra chromosome in the embryo, or the rearrangement of genes which can cause pregnancy loss and birth defects.
When PGT is used to detect single gene disorders, a child has a more than 99% chance of being born without the gene mutation for which the embryos are screened.
The first step for individuals and couples who wish to learn more about PGT is to consult a genetic counselor.
Both the costs and the availability of genetic testing may vary across Canada. You should talk to your doctor or genetics clinic to find out what is available in your area and what is covered under your provincial health care plan. You may also have coverage through your private insurance or employee benefits. You can find out more about PGT from the Canadian Association of Genetic Counsellors here.
- Resources
Rare Disease Information and Support Centre: Information, resources, and support for any rare disease. A free and bilingual professional service.
- Quebec - rqmo.org/rare-disease-information-and-resource-centre/
- Other provinces - Write to info@rqmo.org or call toll-free: 1-888-822-2854
A detailed discussion of genetic dystonias is available from GeneReviews.
Thank you to Dystonia Medical Research Foundation (USA) for allowing us to share this information. The DMRF is a 501(c)(3) non-profit organization dedicated to advancing research for improved dystonia treatments and ultimately a cure, promoting awareness, and supporting the well-being of affected individuals and families.