Primary dystonia is mostly sporadic, with a few family history, autosomal dominant or recessive inheritance, or X chromosome linkage inheritance, which is more common in children or adolescents aged 7~ 15. Primary autosomal dominant torsion spasm is mostly caused by the mutation of DYTl gene located in 9q32-34, and the penetrance rate is 30% ~ 50%. Dopa-responsive dystonia is also autosomal dominant, which is caused by the mutation of guanosine triphosphate cyclohydrolase-1(GCH- 1) gene. On the Philippine island of Pallai, there is a dystonia-Parkinson's syndrome, which is an X-linked recessive inheritance. Familial localized dystonia is usually autosomal dominant inheritance with incomplete penetrance.

Studies have confirmed that peripheral trauma can induce dystonia in primary dystonia gene carriers, such as oral-mandibular dystonia, with a history of facial or tooth injury before illness. In addition, excessive movement of one limb can also induce dystonia. For example, various occupational dystonia, writing spasm, typist spasm, limb spasm of instrument players and athletes, etc. , usually considered as the main function. Therefore, it is speculated that the cause is the reorganization of spinal motor loop or the change of motor sensory connection above spinal level, which leads to the change of basal ganglia function.

Secondary (symptomatic) dystonia refers to all lesions involving new striatum, old striatum, thalamus, locus coeruleus and reticular structure of brain stem. , can cause dystonia symptoms, such as hepatolenticular degeneration, nuclear jaundice, gangliosidosis, globus pallidus melanosis, progressive supranuclear ophthalmoplegia, bilateral basal ganglia calcification, hypoparathyroidism, poisoning, cerebrovascular diseases, etc.

Dopa, phenothiazine, styrene butadiene, metoclopramide, chemotherapy drugs), etc. It is reported that blepharospasm can be caused by dorsal brainstem ischemia or demyelination.

The pathogenesis is unknown. It is reported that the concentrations of neurotransmitters such as norepinephrine, dopamine and serotonin are abnormal in some areas of the brain, but their significance is still unclear. The latest research thinks that the local dystonia is caused by the abnormality of basal ganglia, because the static imaging research has not confirmed the abnormality, while the dynamic imaging research by positron emission tomography (PET) shows that the metabolic rate of caudate nucleus, lentiform nucleus and frontal lobe projection area of dorsal medial thalamus is decreased, so it is considered that the dysfunction of basal ganglia and frontal lobe connection is the main cause of dystonia.