The gene that causes a person’s dystonia is one of the strongest predictors of how well deep brain stimulation will work. A 2020 meta-analysis of genetically confirmed dystonia treated with pallidal DBS found an average motor improvement of 68% in DYT-TOR1A (DYT1) dystonia, 37% in DYT-THAP1 (DYT6) dystonia and 27% in NBIA/PANK2, with TOR1A responding significantly better than the other genes compared.[1]
Myoclonus-dystonia caused by SGCE (DYT11) also responds very well, particularly the jerks. On the other hand, dopa-responsive dystonia (DYT5, GCH1) is treated with medication and does not need surgery. That is why genetic testing is recommended for anyone whose dystonia began before about age 30 or runs in the family.
Dystonia genes and the expected response to DBS
Genetic dystonias are now named by the gene (for example DYT-TOR1A). The older numbered names (DYT1, DYT6…) are still widely used, so we give both.
| Gene (old name) | Typical picture | Response to GPi DBS |
|---|---|---|
| TOR1A (DYT1) | Early-onset generalized dystonia, often starting in a leg or arm in childhood | Excellent: 68% average motor and 69% disability improvement[1] |
| THAP1 (DYT6) | Adolescent or adult onset; face, jaw, voice and neck prominent | Moderate: 37% average motor improvement; speech and voice respond less[1] |
| SGCE (DYT11, myoclonus-dystonia) | Lightning-like jerks of the neck and arms with dystonia, often eased by alcohol | Very good, especially for the jerks; in this group a younger age at onset predicted a smaller benefit[1] |
| KMT2B (DYT28) | Childhood onset, often in the legs, progressing to generalized with jaw and voice involvement | Good in most reported patients[2] |
| TAF1 (DYT3, X-linked dystonia-parkinsonism) | Adult men of Filipino ancestry; dystonia then parkinsonism | Good for dystonia; longer disease duration predicted less benefit[1] |
| GNAL (DYT25), ANO3 (DYT24) | Adult-onset cervical and cranial dystonia, sometimes with tremor | Limited data; responses reported, variable |
| ADCY5 | Childhood-onset dyskinesia with dystonia and chorea | Smaller benefit than TOR1A[1] |
| PANK2 (NBIA / PKAN) | Childhood-onset dystonia with brain iron accumulation | Modest: 27% average motor improvement; can ease severe dystonia and care[1] |
| GCH1 (DYT5, dopa-responsive dystonia) | Childhood leg dystonia, worse in the evening | DBS not indicated. Responds dramatically to medication |
Percentages: improvement in the Burke-Fahn-Marsden motor and disability scores, meta-analysis of published patients. Literature data, not our own case series; individual results vary.
DYT1 (TOR1A) dystonia and DBS
DYT1 is the classic early-onset generalized dystonia. It usually begins in a leg or arm in childhood and spreads to the trunk and other limbs. It is the genetic dystonia with the best response to pallidal DBS, and the response is better when surgery is done earlier: in TOR1A patients, a longer duration of dystonia and older age at onset were associated with smaller improvement.[1]
DYT6 (THAP1) dystonia and DBS
DYT6 tends to involve the face, jaw, voice and neck, which are the regions that respond more slowly and less completely to stimulation. The 37% average motor improvement is still meaningful for many patients, and limb and trunk symptoms usually improve more than speech.[1] Expectations should be discussed clearly before surgery.
Myoclonus-dystonia (DYT11, SGCE) and DBS
In our own case series, patients treated with DBS for cervical dystonia, Meige syndrome and myoclonus-dystonia have shown more than 90% improvement in their symptoms, based on clinical assessment and documented on video. Individual results vary.
Myoclonus-dystonia combines quick jerks (myoclonus), mainly of the neck, shoulders and arms, with dystonia such as cervical dystonia or writer’s cramp. Pallidal DBS usually controls the jerks particularly well, and the dystonia improves too. Some centers use the thalamic target for jerk-predominant cases.
Should I have genetic testing before DBS?
For early-onset, generalized or familial dystonia, yes: the result helps predict the benefit and rules out dopa-responsive dystonia. A negative test does not mean DBS will not work. Many patients with idiopathic isolated dystonia, in whom no gene is found, respond very well.
Frequently asked questions
Is DBS effective for DYT1 dystonia?
Yes. DYT1 (TOR1A) dystonia responds best of all genetic dystonias, with a 68% average motor improvement in a meta-analysis.[1]
Does DBS work for DYT6 dystonia?
It helps, but less than in DYT1: about 37% motor improvement on average, with smaller effects on speech.[1]
Can I have DBS without genetic testing?
Yes. Genetic testing helps predict results but is not required. Many patients with no identified gene benefit greatly.
Is my dystonia going to be passed to my children?
Some genetic dystonias are inherited with a 50% chance of passing on the gene, but many carriers never develop symptoms. A genetic counsellor can explain your personal risk.
Sources
- Artusi CA, Dwivedi A, Romagnolo A, et al. Differential response to pallidal deep brain stimulation among monogenic dystonias: systematic review and meta-analysis. J Neurol Neurosurg Psychiatry. 2020;91(4):426–433. Source
- Meyer E, Carss KJ, Rankin J, et al. Mutations in the histone methyltransferase gene KMT2B cause complex early-onset dystonia. Nat Genet. 2017;49(2):223–237. Source