title: Nonparametric linkage analysis between schizophrenia and candidate genes of dopaminergic and serotonergic systems.
abstract: BACKGROUND
  Alterations in dopaminergic and serotonergic systems have been implicated in the pathophysiology of schizophrenia for many years. This study was performed to assess the possible involvement of the dopamine receptor genes D2 (DRD2), D3, D4, serotonin receptor genes 1Da, 1Db, and 2A in the etiology of schizophrenia.
  
  
  METHODS
  We examined 33 multiplex schizophrenic families from Portugal.
  
  
  RESULTS
  Linkage analysis performed by GENEHUNTER showed nonsignificant linkage for these genes. A maximum nonparametric linkage score of 1.635 (P=.032) at DRD2 gene was observed, and this finding suggests DRD2 gene for further studies.
  
  
  CONCLUSIONS
  the polymorphisms studied at dopamine receptor genes D3, D4, serotonin receptor genes 1Da, 1Db, and 2A do not have a major effect in susceptibility to schizophrenia in a Portuguese population.
authors.affiliation: Department of Neurochemistry, University of Coimbra, Coimbra, Portugal. aldachico@yahoo.com
authors.forename: Alda M
authors.initials: AM
authors.lastname: Ambrósio
authors.forename: James L
authors.initials: JL
authors.lastname: Kennedy
authors.forename: Fabio
authors.initials: F
authors.lastname: Macciardi
authors.forename: Isabel
authors.initials: I
authors.lastname: Coelho
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Soares
authors.forename: Catarina R
authors.initials: CR
authors.lastname: Oliveira
authors.forename: Michele T
authors.initials: MT
authors.lastname: Pato
authors.forename: Carlos N
authors.initials: CN
authors.lastname: Pato
mesh_terms: D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D004252:DNA Mutational Analysis; D004298:Dopamine / Q000235:genetics*; D008040:Genetic Linkage / Q000235:genetics*; D006801:Humans; D017354:Point Mutation / Q000235:genetics; D012559:Schizophrenia / Q000453:epidemiology* / Q000235:genetics*; D012701:Serotonin / Q000235:genetics*; D018709:Statistics, Nonparametric
chemical_list: D012701:Serotonin; D004298:Dopamine