title: Epigenetic evidence for involvement of the oxytocin receptor gene in obsessive-compulsive disorder.
abstract: Obsessive-compulsive disorder (OCD) is a chronic neurodevelopmental disorder that affects up to 3% of the general population. Although epigenetic mechanisms play a role in neurodevelopment disorders, epigenetic pathways associated with OCD have rarely been investigated. Oxytocin is a neuropeptide involved in neurobehavioral functions. Oxytocin has been shown to be associated with the regulation of complex socio-cognitive processes such as attachment, social exploration, and social recognition, as well as anxiety and other stress-related behaviors. Oxytocin has also been linked to the pathophysiology of OCD, albeit inconsistently. The aim of this study was to investigate methylation in two targets sequences located in the exon III of the oxytocin receptor gene (OXTR), in OCD patients and healthy controls. We used bisulfite sequencing to quantify DNA methylation in peripheral blood samples collected from 42 OCD patients and 31 healthy controls.
  
  
  
  We found that the level of methylation of the cytosine-phosphate-guanine sites in two targets sequences analyzed was greater in the OCD patients than in the controls. The higher methylation in the OCD patients correlated with OCD severity. We measured DNA methylation in the peripheral blood, which prevented us from drawing any conclusions about processes in the central nervous system.
  
  
  
  To our knowledge, this is the first study investigating DNA methylation of the OXTR in OCD. Further studies are needed to evaluate the roles that DNA methylation and oxytocin play in OCD.
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil. carolinacappi@gmail.com.
authors.forename: Carolina
authors.initials: C
authors.lastname: Cappi
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Juliana Belo
authors.initials: JB
authors.lastname: Diniz
authors.affiliation: Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil.
authors.forename: Guaraci L
authors.initials: GL
authors.lastname: Requena
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Tiaya
authors.initials: T
authors.lastname: Lourenço
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Bianca Cristina Garcia
authors.initials: BC
authors.lastname: Lisboa
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Marcelo Camargo
authors.initials: MC
authors.lastname: Batistuzzo
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Andrea H
authors.initials: AH
authors.lastname: Marques
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Marcelo Q
authors.initials: MQ
authors.lastname: Hoexter
authors.affiliation: Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Pereira
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Euripedes Constantino
authors.initials: EC
authors.lastname: Miguel
authors.affiliation: Department of Psychiatry, School of Medicine, University of São Paulo, R. Dr. Ovídio Pires de Campos, 785, 3º andar, sala 9, São Paulo, SP, 05403-010, Brazil.
authors.forename: Helena
authors.initials: H
authors.lastname: Brentani
mesh_terms: D000328:Adult; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005091:Exons; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000097:blood / Q000235:genetics*; D011569:Psychiatric Status Rating Scales; D018045:Receptors, Oxytocin / Q000097:blood / Q000235:genetics*; D012720:Severity of Illness Index
chemical_list: C569600:OXTR protein, human; D018045:Receptors, Oxytocin
keywords: Methylation; OCD; Oxytocin receptor gene (OXTR)