Clinical characteristics and PRRT2 gene mutation analysis of sporadic patients with paroxysmal kinesigenic dyskinesia in China.

OBJECTIVE: As a rare type of movement disorder, paroxysmal kinesigenic dyskinesia mainly affects children and is associated with PRRT2 gene mutation. The objective of our study is to identify whether the sporadic patients share the same genotype-phenotype correlations as familial patients in China. PATIENTS AND METHODS: We investigated the clinical characteristics and PRRT2 gene mutations of 15 sporadic patients with paroxysmal kinesigenic dyskinesia in china. The clinical and investigational data of our patients was recorded and analyzed meticulously.
RESULTS: We have summarized the clinical characteristics and PRRT2 gene mutation of Chinese sporadic patients with paroxysmal kinesigenic dyskinesia. Male patients have a high incidence of paroxysmal kinesigenic dyskinesia. The age of onset is between 6 and 16 years (average 10.27±3.43 years; median 10 years) and the course of disease is between 0.3 and 14 years (average 5.95±4.55years; median 6 years). The attack usually begins in childhood or adolescence and diminishing with age. Paroxysmal dystonia on the limbs is the predominant clinical manifestation of our patients. Tremor on two hands might be a common combined symptom. Carbamazepine is an effective drug for our patients. Two variants PRRT2c.412C>G, PRRT2c.439G>C and one mutation PRRT2 c.649dupC was identified in our patients.
CONCLUSIONS: Genotype-phenotype correlations in sporadic patients with paroxysmal kinesigenic dyskinesia remain unclear in China. Further studies involving larger patients on the clinical characteristics should be carry out. Carbamazepine is the first-choice drug and PRRT2 c.649dupC mutation is a hot-spot mutation in Chinese sporadic patients with paroxysmal kinesigenic dyskinesia.