Focus On: DYT1 Dystonia

A form of hereditary, generalized dystonia

DYT1 DystoniaDYT1 dystonia, also known as early-onset, torsion dystonia, is a severe form of hereditary, generalized dystonia. Generalized dystonia refers to dystonia that is not limited to a single part of the body but affects multiple muscle groups throughout the body. Generalized dystonia typically affects muscles in the torso and limbs, and sometimes the neck, face, and vocal cords. Patients have difficulty moving their bodies freely and controlling their body movements.

DYT1 dystonia typically begins around age 10 with the twisting of a foot or arm. Symptoms tend to begin in one body part and progress to involve additional limbs and the torso. Symptoms tend to be less severe the later in life they start and if they start in a hand or arm.

Most cases of early onset torsion dystonia are directly associated with a mutation that affects the DYT1 gene, which scientists discovered in 1997 with the support of the DMRF. In its normal state, the gene is responsible for providing the body with the genetic instructions to produce a protein called torsinA. The mutated DYT1 gene results in an abnormal form of torsinA, and this abnormal protein starts a chain reaction of biochemical processes that somehow disrupts the communication between the brain and muscles. This disruption of the nervous system leads to the debilitating physical symptoms of DYT1 dystonia.

DYT1 dystonia is dominantly inherited, meaning that only one parent needs to have the mutation for a child to inherit the disorder. However, the DYT1 mutation also exhibits reduced penetrance, which means that not every person who inherits the mutated gene will develop symptoms. Only about 30% of individuals who have the DYT1 genetic mutation will develop dystonia. Research is ongoing to better understand this phenomenon.

If a person does not manifest symptoms before the age of 28 years, they will usually remain symptom free for life—even if they have the DYT1 mutation. The DYT1 mutation is responsible for about 90% of early onset generalized dystonia in individuals of Ashkenazi Jewish ancestry and up to about 50% of early onset generalized dystonia in other ethnicities.

Treatment
Individuals with dystonia are encouraged to seek treatment from a movement disorder neurologist or child neurologist with special training in movement disorders. A multidisciplinary team of expert medical professionals may be appropriate to tailor treatment to the needs of the patient.

A movement disorder specialist will develop a treatment plan that is customized to each patient. Most individuals require a combination of therapies. Treatment to lessen dystonia symptoms may include oral medications such as anticholinergics, baclofen, and benzodiazepines combined with botulinum neurotoxin injections, and/or surgical procedures such as deep brain stimulation (DBS). Research suggests that individuals with DYT1 dystonia tend to have the best outcomes from DBS compared to other forms of generalized dystonia.

Genetic testing is available to test for the DYT1 gene mutation. Individuals and families who wish to learn more about genetic testing for DYT1 and other genetic mutations associated with certain dystonias are advised to consult a genetic counselor.

“Understanding the genetic implications of DYT1 dystonia can be overwhelming,” said Deborah Raymond, MS, genetic counselor at Mount Sinai Health System, New York City. “Genetic counselors are trained to help people decide whether getting a genetic test is right for them. They will also help interpret test results and offer counsel on the significance of the results for that family.”

Specific treatment may be needed to prevent loss of motion in the joints and/or curvature of the spine due to the dystonic postures. Complementary therapies to support overall functioning and wellness may include occupational therapy, physical therapy, speech/voice therapy, and other interventions depending on a person’s symptoms. Individuals with childhood onset generalized dystonia may have increased risk for depression, so monitoring and addressing emotional and mental health is often an important part of the treatment strategy.

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