title: Genotype-phenotype correlation in a cohort of paroxysmal kinesigenic dyskinesia cases.
abstract: BACKGROUND
  Recently, PRRT2 gene mutations have been identified as a causative factor of paroxysmal kinesigenic dyskinesia (PKD). However, evidence is still lacking with respect to the genotype to phenotype correlation in PKD patients.
  
  
  METHODS
  We recruited a cohort of PKD patients with or without PRRT2 mutations for the study, and followed them for 6 months to observe the response to carbamazepine treatment.
  
  
  RESULTS
  Thirty-four participants were included in this study; 16 patients were positive for a hot-spot p.R217Pfs 8 heterozygous PRRT2 gene mutation, while the other 18 patients were negative for PRRT2 gene mutations. PRRT2 mutations were found to be associated with a younger age of onset, bilateral presence and a higher frequency of attacks. Furthermore, the follow-up study revealed that p.R217Pfs 8-positive patients showed dramatic improvement with complete abolition of dyskinetic episodes with carbamazepine treatment, while only 7 of the 18 patients without PRRT2 mutations showed a response to the antiepileptic drug.
  
  
  CONCLUSIONS
  Our study indicated that positivity for PRRT2 mutation is a predictor of younger age of onset and more frequent of attacks in PKD patients. Interestingly, the presence of PRRT2 mutations also predicted a good response to carbamazepine therapy, especially at low dose. Therefore, genetic testing shows potential clinical significance for guiding the choice of medication for individual PKD cases.
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Cheng-Yuan
authors.initials: CY
authors.lastname: Mao
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Chang-He
authors.initials: CH
authors.lastname: Shi
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Song
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ji
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Qin
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Li
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Shang
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China.
authors.forename: Shi-Lei
authors.initials: SL
authors.lastname: Sun
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000 Henan, People's Republic of China. Electronic address: xuyuming@zzu.edu.cn.
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002819:Chorea / Q000235:genetics* / Q000503:physiopathology*; D015331:Cohort Studies; D004421:Dystonia; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010641:Phenotype; D055815:Young Adult
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C569370:PRRT2 protein, human
keywords: Carbamazepine; Drug response; Genotype; PRRT2; Paroxysmal kinesigenic dyskinesia; Phenotype