People with dystonia may be concerned that their children are at risk of inheriting the disorder.
Being informed about the genetics of dystonia can also be important in the diagnosis and treatment process. There are forms of dystonia that are known to be genetically inherited and forms that may or may not have a genetic component — researchers simply cannot confirm or rule it out at this time. Currently, several dystonia genes with numerous mutations and other abnormalities have been identified and linked to specific forms of dystonia.
A genetic counsellor can help individuals and families learn more about the genetics of dystonia and whether they are eligible for genetic testing. Researchers are actively seeking to better understand the genetics of all dystonias and to identify additional gene mutations.
What forms of dystonia are inherited?
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 children. This is especially true if other family members exhibit symptoms or are already diagnosed.
Genetic dystonias that are known to run in families include early onset dystonia, primary cervical dystonia, dopa responsive dystonias, myclonus dystonia, paroxysmal dystonias/dyskinesias, rapid-onset dystonia-parkinsonism, X-linked dystonia-parkinsonism, and others.
However, as will be explained below, not everyone who inherits a dystonia-causing gene mutation will develop symptoms. Also, some people develop dystonia due to a gene 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.
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 are in all likelihood not at increased risk of inheriting a known dystonia-causing mutation. However, researchers do not know at this time whether individuals who develop secondary dystonias 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 dystonias. Moreover, dystonia can occur as a system of various genetically-caused diseases, in which the inheritance patterns vary.
Dystonia gene mutations
Every gene consists of DNA that contains a code for a specific protein. Proteins participate in virtually every process in the human body. When a gene becomes mutated, this changes the protein associated with that gene and, ultimately, how that protein functions. When a changed protein cannot properly fulfill its function, this may disrupt normal biological processes and lead to a disease or disorder, including dystonias.
Identifying dystonia gene mutations is important for patients because it may clarify notoriously complex dystonia diagnosis, point to specific treatments, and give families the information needed to explore, if they choose, measures to reduce the risks of dystonia in future generations.
Dystonia mutations also give researchers an important clue to help unravel the complicated series of biochemical events that causes dystonia symptoms. Every time a new dystonia gene or gene mutation is discovered, it provides a new therapeutic target for new treatment approaches.
One of the greatest mysteries that dystonia researchers are working to solve is the fact that not everyone who inherits a dystonia gene mutation will develop symptoms.
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.