title: [Timekeeping molecules: implications for circadian phenotypes].
abstract: OBJECTIVE
  The aim of this study was to review the molecular chronobiology studies in the last 36 years in order Eto point out the advances in this area to health professionals.
  
  
  METHODS
  We searched in the PubMed and Scopus data banks for articles related with human molecular chronobiology. The keywords used were 'clock genes, circadian rhythms, diurnal preference, delayed sleep phase syndrome, advanced sleep phase syndrome, photoperiod and mood disorder'.
  
  
  CONCLUSIONS
  The knowledge about molecular mechanism of circadian rhythms increased a lot in the last years and now we are able to better understand the details of molecular processes involved in circadian and sleep regulation. Studies show that polymorphisms in clock genes are associated with sleep and mood disorders. These studies will be helpful to further elucidate the regulation of molecular mechanisms of circadian rhythms.
  
  
  CONCLUSIONS
  The development of these studies in molecular chronobiology can be helpful to treat circadian and mood disorders and to prevent health risks caused by intercontinental flights (Jet Lag), nocturnal or shift work schedule.
authors.affiliation: Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
authors.forename: Danyella Silva
authors.initials: DS
authors.lastname: Pereira
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.forename: Mario
authors.initials: M
authors.lastname: Pedrazzoli
mesh_terms: D001683:Biological Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics*; D006801:Humans; D019964:Mood Disorders / Q000235:genetics*; D010641:Phenotype; D012890:Sleep / Q000235:genetics*; D012894:Sleep Stages / Q000502:physiology; D012893:Sleep Wake Disorders / Q000235:genetics* / Q000503:physiopathology