Paroxysmal kinesigenic dyskinesia(PKD)is an autosomal dominant movement disorder with characteristics of involuntary attacks precipitated by sudden movements.Using whole-exome sequencing followed by Sanger sequencing,we identified the gene encoding the proline-rich transmembrane protein 2(PRRT2)as a causative gene for PKD.Our results also showed that PRRT2 c.649dupC mutation was a high frequent mutation,which was supported by other studies.We then recruited 9 sporadic Chinese PKD patients including one Mongolian patient,and found that c.649dupC mutation was detected in the Mongolian patient but not in his parents.Haplotype analysis confirmed the biological relationship among the trio,suggesting c.649dupC mutation derived from de novo in this patient.Our results combining other reports implied that c.649dupC mutation was a hotspot mutation within PRRT2.Furthermore,we analyzed the genotype-phenotype correlation and drug response in 81 PKD cases.We found that PRRT2 mutation carriers and non-PRRT2 mutation carriers had different phenotypes.Most importantly,we found that all PRRT2 mutation carriers responded completely to low-dose carbamazepine,while 94%of the non-PRRT2 mutation carriers did not have a full response to carbamazepine,even after the dose was increased.