• Changes in clinical characteristics of PKC relative to the baseline. [ Time Frame: up to 10 years ]
  Improvement or worsening of the attacks relative to the baseline state assessed by a questionnaire, categorized as following; 1, full remission (absence of the attacks); 2, improvement (more than 50% decreased mean frequency of the attacks); 3, worsening (increased frequency of the attacks).
• Changes in clinical characteristics of PKC over the last year. [ Time Frame: up to 10 years ]
  Improvement or worsening of the attacks over the last year assessed by a questionnaire, categorized as following; 1, full remission (absence of the attacks); 2, improvement (more than 50% decreased mean frequency of the attacks); 3, worsening (increased frequency of the attacks).
• Changes in medication history of PKC over the last year. [ Time Frame: up to 10 years ]
  Continuation or discontinuation of the medication for relief of the attacks assessed by a questionnaire, categorized as following; 1, continuation of medication; 2, discontinuation of medication.

PKC is a hyperkinetic movement disorder including dystonia, chorea, athetosis, or ballism, which are characteristically triggered by a sudden movement from rest. The prevalence of this disorder is estimated to be 1 in 150,000 population. Males are more commonly affected than females, and the age of onset is typically in childhood or adolescence. PKC is mainly a familial disorder with autosomal dominant inheritance and incomplete penetrance, but it can occur sporadically. The PRRT2 (proline-rich transmembrane protein 2) gene is believed to be the major causative gene.

The prognosis of PKC is usually favorable. The severity and frequency of the attacks are reduced by anticonvulsant medication such as carbamazepine, and the number of the attacks decreases at the age of 20-30 years. However, there has been little study of long-term prognosis of PKC, and no study has been conducted in Korean population.

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Inclusion Criteria:

• Male or female PKC patients who were18 years of age and older
• Subjects were diagnosed as paroxysmal kinesigenic choreoathetosis (PKC)
• Subjects were enrolled voluntarily and understood the contents of this trial

Exclusion Criteria:

• Existence of lesions on the brain
• Existence of neurological deficit that suspected lesions on the brain
• Existence of epileptiform discharges on electroencephalogram
• Subjects with secondary PKC which was caused by other disorder or illness
• Existence of illness or problems which made difficult to be enrolled to this trial judged by clinicians