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Myoclonus-dystonia
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Myoclonus-dystonia

Myoclonus-dystonia is a movement disorder characterized by rapid, involuntary muscle jerks and abnormal posturing that typically begins in childhood. This genetic condition is also frequently associated with psychological disorders such as depression, anxiety, and obsessive-compulsive disorder.

Overview & Symptoms

Myoclonus-dystonia is a movement disorder that typically affects the neck, torso, and arms. Individuals with this condition experience quick, involuntary muscle jerks or twitches (myoclonus). About half of individuals with myoclonus-dystonia develop dystonia, which is involuntary tensing of various muscles that causes unusual positioning. In myoclonus-dystonia, dystonia often affects one or both hands, causing writer's cramp, or the neck, causing the head to turn (torticollis).

The movement problems usually first appear in childhood or early adolescence with the development of myoclonus. In most cases, the movement problems remain stable throughout life. In some adults, myoclonus improves with alcohol consumption, which can lead to affected individuals self-medicating and developing alcohol use disorder.

People with myoclonus-dystonia often develop psychological disorders such as depression, anxiety, panic attacks, and obsessive-compulsive disorder (OCD).

Frequency

The prevalence of myoclonus-dystonia in Europe is estimated to be 1 in 500,000 individuals. Its prevalence elsewhere in the world is unknown.

Causes & Genetic Factors

Mutations in the SGCE gene cause 30 to 50 percent of cases of myoclonus-dystonia. The SGCE gene provides instructions for making a protein called epsilon (ε)-sarcoglycan, whose function is unknown. The ε-sarcoglycan protein is located within the outer membrane of cells in many tissues, but it is most abundant in nerve cells in the brain and in muscle cells.

SGCE gene mutations that cause myoclonus-dystonia result in a shortage (deficiency) of functional ε-sarcoglycan protein. This lack of functional protein seems to affect the regions of the brain involved in coordinating and controlling movements (and the basal ganglia, respectively). It is unknown why SGCE gene mutations seem to affect only these areas of the brain.

Mutations in multiple other genes are associated with myoclonus-dystonia. Mutations in each of these genes cause a small percentage of cases. These genes are primarily active (expressed) in the brain and mutations likely lead to impairment of normal movement.

Some people with myoclonus-dystonia do not have an identified mutation in any of the known associated genes. The cause of the condition in these individuals is unknown.

Genes Associated with Myoclonus-dystonia

  • RELN
  • SGCE
  • KCTD17

Inheritance Pattern

In cases in which the genetic cause is known, myoclonus-dystonia is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In cases in which the cause of the condition is unknown, the inheritance is unclear.

When caused by SGCE gene mutations, myoclonus-dystonia occurs only when the mutation is inherited from a person's father. People normally inherit one copy of each gene from their mother and one copy from their father. For most genes, both copies are active, or "turned on," in all cells. For a small subset of genes, however, only one of the two copies is active. For some of these genes, only the copy inherited from a person's father (the paternal copy) is active, while for other genes, only the copy inherited from a person's mother (the maternal copy) is active. These differences in gene activation based on the gene's parent of origin are caused by a phenomenon called genomic imprinting.

Because only the paternal copy of the SGCE gene is active, myoclonus-dystonia occurs when mutations affect the paternal copy of the SGCE gene. Mutations in the maternal copy of the gene typically do not cause any health problems. Rarely, individuals who inherit an SGCE gene mutation from their mothers will develop features of myoclonus-dystonia. It is unclear why a gene that is supposed to be turned off is active in these rare cases.

Other genes associated with myoclonus-dystonia are not imprinted, and mutations that cause the condition can be inherited from either parent.

Other Names for This Condition

  • Dystonia 11
  • DYT11
  • Myoclonus-dystonia syndrome

Frequently Asked Questions

Diagnosis relies on the specific combination of rapid, shock-like muscle jerks (myoclonus) and sustained muscle contractions causing abnormal posturing (dystonia), often affecting the hands or neck. Unlike essential tremor, which is a rhythmic shaking, myoclonus is brief and irregular. It is distinguished from epilepsy because the jerks are not associated with loss of consciousness or post-ictal confusion, and EEG findings are typically normal or show non-specific changes rather than epileptiform discharges. Genetic testing for SGCE mutations can further confirm the diagnosis.
significant proportion of individuals with myoclonus-dystonia develop comorbid psychiatric conditions, including depression, anxiety, panic attacks, and obsessive-compulsive disorder. These psychological issues can be as debilitating as the physical movement symptoms and require integrated treatment. Managing the mental health aspects is crucial for quality of life, as untreated psychiatric disorders can exacerbate stress, which may in turn worsen the physical myoclonus and dystonia.
There is currently no cure for myoclonus-dystonia, but the condition is generally non-progressive. In most cases, the movement problems stabilize after onset in childhood or early adolescence and do not worsen significantly over time. While the physical symptoms remain stable, the focus of management shifts to controlling the myoclonus and dystonia with medications and addressing the associated psychological challenges to maintain functional independence.
lcohol can temporarily reduce the frequency and severity of myoclonus in many individuals with myoclonus-dystonia, likely by enhancing the activity of inhibitory neurotransmitters in the brain. However, this is not a recommended long-term treatment strategy. Because the relief is temporary and the condition is chronic, reliance on alcohol for symptom management frequently leads to alcohol use disorder, which poses significant health risks and complicates the overall clinical picture.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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