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DYT1 Generalised Dystonia

DYT1 generalised dystonia is a neurological movement disorder that is characterised by involuntary, sustained, twisting muscle spasms. Onset is typically in mid to late childhood.  Symptoms tend to start in one limb then often spread to other limbs and adjoining body areas leading to progressive disability.

If you have just received a diagnosis there is help and support available - please see ‘Further information and support’ below for links to valuable resources. It is also important to note that not every person with this condition experiences all the symptoms described and it is worth talking to your doctor or other relevant healthcare specialists to discuss you or your family member’s individual case.

Inheritance

DYT1 generalised dystonia is an autosomal dominant condition, however, it has reduced penetrance meaning that only about 30% of people that carry the mutation are likely to develop symptoms.

Prevalence

The carrier frequency in the Ashkenazi Jewish population is approximately 1 in 1000 to 1 in 3000, and the disorder incidence is estimated to be between 1 in 3000 to 1 in 9000 given the reduced penetrance. This prevalence is 3-5 times higher than in the general population.

Of all the types of dystonia, only the DYT1 generalised form (also known as early-onset, primary torsion or idiopathic torsion dystonia) is more prevalent among Ashkenazi Jews relative to the general population.

Symptoms

Age of onset and severity of the disorder is variable, however, common signs and symptoms include:

  • Turning in of the foot and/leg and/or arm
  • Twisted postures of the limbs and trunk
  • Muscle spasms / contractions, with or without pain
  • Walking with bending and twisting of the torso
  • Rapid, sometimes rhythmic, jerking movements

Symptoms often become worse with stress and tiredness, however, usually disappear whilst the affected individual is sleeping. Intelligence, strength, and functioning of the senses are all normal.


Please click on the titles to open and close the following information sections.

The disorder is caused by a mutation in the DYT1 gene that codes for the protein torsin A. The mutation is thought to affect functioning of the basal ganglia, which are structures deep within the brain involved in movement and posture control. The exact way in which these structures malfunction in dystonia is not clear, however much research is currently being carried out to progress understanding of the condition.

Although there is no cure at this time, various treatments are available to manage disorder symptoms. Oral medications can be taken to help control involuntary spasms. Botulinum toxin injections can be given to treat specific affected body parts. Relaxation techniques, hypnosis, and physical therapy also can be helpful in symptom management.

For more severe cases, surgery may be appropriate. DBS (deep brain stimulation) surgery has been found to be very effective in controlling symptoms in some DYT1 patients. 

Disorder progression is variable and is partly influenced by age of onset and body area where the symptoms begin. If symptoms have not developed by age 30, they are unlikely to do so later in life.

Where symptoms do develop, the younger the age of onset, the more likely the symptoms will begin in a lower limb, spread upwards and possibly become generalized. When symptoms begin in the arm or neck, onset tends to be slightly later and the progression to other body areas may be less likely.

Symptom progression often plateaus after a few years, after which further significant deterioration is unusual. Typically life expectancy is unaffected.

Given the unusual presentation of symptoms of DYT1, obtaining a prompt and accurate diagnosis can sometimes be difficult.  Through appropriate referral to a neurologist with knowledge of movement disorders, a diagnosis can easily be made using various physical and neurological examinations together with patient information. A diagnosis can be confirmed using genetic testing which involves a simple blood test.

carrier testing is possible and analyzes DNA to identify a mutation (a 3-base-pair GAG deletion) in the DYT1 gene which accounts for over 90% of cases of the disorder in Ashkenazi Jews and about 50% of the case in non-Jews. Accuracy of the test in detecting this mutation is over 99%.

prenatal testing is also available. This can identify the presence of the mutation but cannot predict whether or not the foetus will be affected, age of onset or symptom severity.

genetic counselling is strongly recommended for anyone with a family history of DYT1 generalised dystonia.

For more information on counselling and testing, please refer to the testing area.

The Dystonia Society

This UK-wide charity provides a wide range of services, advice and information for anyone affected by dystonia. It aims to facilitate access to the most appropriate treatment, support and information available; to raise awareness of the condition; and to promote research. Their website includes information about all types of dystonia, living with the condition, support services, research, and links to additional resources. This site also contains a forum for support and information.

Helpline number: 0845 458 6322 or 020 7793 3658
Office number: 0845 458 6211

Dystonia Medical Research Foundation (USA)

The DMRF is a USA-based organisation that provides support and information to those affected by dystonia and is deeply involved in dystonia-related research initiatives. Their website provides information about all types of dystonia, past and current research, treatment, support, and activities to raise awareness and progress understanding and treatment. It also has a sister organisation in Canada - Dystonia Medical Research Foundation Canada.

European Dystonia Federation (Europe)

The EDF is a collaborative effort by European dystonia groups to raise the profile of dystonia and influence health and government policies at a European level. Their website includes links to member organisations, the dystonia international patient registry and other resources.

To find out more about general resources relevant to Jewish genetic disorders, please visit our resources and support section.

 

Written by Jnetics
Approved by: Professor Patricia Limousine, Professor in Clinical Neurology and Honorary Consultant Neurologist, UCL Institute of Neurology, Queens Square
Last review: 20.1.2015