title: A length polymorphism in the circadian clock gene Per3 is linked to delayed sleep phase syndrome and extreme diurnal preference.
abstract: OBJECTIVE
  To investigate the link between extreme diurnal preference, delayed sleep phase syndrome, and a length polymorphism in Per3.
  
  
  METHODS
  Subjects were genotyped using polymerase chain reaction.
  
  
  METHODS
  Subjects with defined diurnal preference as determined by the Horne-Ostberg questionnaire and patients with delayed sleep phase syndrome.
  
  
  RESULTS
  The Per3 polymorphism correlated significantly with extreme diurnal preference, the longer allele associating with morningness and the shorter allele with eveningness. The shorter allele was strongly associated with the delayed sleep phase syndrome patients, 75% of whom were homozygous.
  
  
  CONCLUSIONS
  The length of the Per3 repeat region identifies a potential genetic marker for extreme diurnal preference.
authors.affiliation: Centre for Chronobiology, School of Biomedical and Life Science, University of Surrey, Guildford GU2 7XH, UK.
authors.forename: Simon N
authors.initials: SN
authors.lastname: Archer
authors.forename: Donna L
authors.initials: DL
authors.lastname: Robilliard
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Skene
authors.forename: Marcel
authors.initials: M
authors.lastname: Smits
authors.forename: Adrian
authors.initials: A
authors.lastname: Williams
authors.forename: Josephine
authors.initials: J
authors.lastname: Arendt
authors.forename: Malcolm
authors.initials: M
authors.lastname: von Schantz
mesh_terms: D000293:Adolescent; D000328:Adult; D002755:Choice Behavior; D002940:Circadian Rhythm / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D011110:Polymorphism, Genetic / Q000235:genetics*; D020178:Sleep Disorders, Circadian Rhythm / Q000235:genetics*; D011795:Surveys and Questionnaires; D014157:Transcription Factors
chemical_list: D009687:Nuclear Proteins; C512644:PER3 protein, human; D056950:Period Circadian Proteins; D014157:Transcription Factors