title: PERIOD3 polymorphism is associated with sleep quality recovery after a mild traumatic brain injury.
abstract: OBJECTIVE
  Mild traumatic brain injury (mTBI) causes transient sleep disorders and circadian dysrhythmia. One of the clock genes, PERIOD3 (PER3), regulates the circadian rhythm and contains a genetic polymorphism, namely a variable-number tandem repeat in the coding area with either four or five repeats. PER3(5) carriers are inclined to have a morning preference and associated with higher risk of bipolar disorder and diabetes. This study investigated the effects of PER3 polymorphism on sleep quality changes after mTBI.
  
  
  METHODS
  From May 2012 to May 2014, a total of 96 mTBI patients completed the baseline (1 week after mTBI) and follow-up (6 weeks after mTBI) assessments, including the Pittsburgh Sleep Quality Index (PSQI) and anxiety and depression questionnaires. Statistics were analyzed using the Mann-Whitney U test, Wilcox signed-rank test or chi-squared test.
  
  
  RESULTS
  Among the 96 patients, 24 were heterozygous PER3(5) carriers (PER3(4/5)), and the rest of 72 were PER3(5) noncarriers (PER3(4/4)). The subscale of PSQI questionnaire results indicated that the PER3(5) allele was associated with significant sleep duration shortening, but improvement in overall sleep quality. Furthermore, analyzing patients with sleep disturbance at the baseline (PSQI >5) revealed that only the PER3(5) noncarriers exhibited a significant improvement in overall PSQI scores.
  
  
  CONCLUSIONS
  PER3(5) carriers exhibited sleep duration shortening and improved daytime function 6 weeks after mTBI compared with the baseline values. On the other hand, among poor sleepers, PER3(5) carriers did not embrace a significant improvement of overall PSQI scores as noncarriers. The underlying mechanisms and clinical significances must be investigated further.
authors.affiliation: Department of Neurology, Taipei Medical University-Shuang Ho Hospital, Taiwan.
authors.forename: Chien-Tai
authors.initials: CT
authors.lastname: Hong
authors.affiliation: Department of Emergency Medicine, Taipei Medical University-Shuang Ho Hospital, Taiwan; Graduate Institute of Clinical Medicine, Taipei Medical University, Taiwan.
authors.forename: Chung-Shun
authors.initials: CS
authors.lastname: Wong
authors.affiliation: Department of Emergency Medicine, Taipei Medical University-Shuang Ho Hospital, Taiwan; Department of Emergency Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taiwan; Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taiwan.
authors.forename: Hon-Ping
authors.initials: HP
authors.lastname: Ma
authors.affiliation: Department of Neurology, Taipei Medical University-Shuang Ho Hospital, Taiwan; Sleep Center, Taipei Medical University-Shuang Ho Hospital, Taiwan; Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan.
authors.forename: Dean
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Neurology, Taipei Medical University-Shuang Ho Hospital, Taiwan; Sleep Center, Taipei Medical University-Shuang Ho Hospital, Taiwan.
authors.forename: Yao-Hsien
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Department of Neurosurgery, Taipei Medical University Hospital, Taiwan.
authors.forename: Chung-Che
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, Taipei Medical University-Shuang Ho Hospital, Taiwan.
authors.forename: Chien-Min
authors.initials: CM
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Taipei Medical University-Shuang Ho Hospital, Taiwan.
authors.forename: Yu-Kai
authors.initials: YK
authors.lastname: Su
authors.affiliation: Department of Neurosurgery, Wan Fang Hospital, Taipei Medical University, Taiwan.
authors.forename: Kuo-Hsing
authors.initials: KH
authors.lastname: Liao
authors.affiliation: Department of Emergency Medicine, Taipei Medical University-Shuang Ho Hospital, Taiwan. Electronic address: juchi@tmu.edu.tw.
authors.forename: Ju-Chi
authors.initials: JC
authors.lastname: Ou
authors.affiliation: Department of Neurology, Taipei Medical University-Shuang Ho Hospital, Taiwan; Sleep Center, Taipei Medical University-Shuang Ho Hospital, Taiwan; Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan. Electronic address: chaurjongh@tmu.edu.tw.
authors.forename: Chaur-Jong
authors.initials: CJ
authors.lastname: Hu
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000150:complications / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D056950:Period Circadian Proteins / Q000235:genetics*; D020127:Recovery of Function / Q000235:genetics*; D012890:Sleep / Q000235:genetics*; D012893:Sleep Wake Disorders / Q000209:etiology / Q000235:genetics*
chemical_list: C512644:PER3 protein, human; D056950:Period Circadian Proteins