title: Rare copy number variants: a point of rarity in genetic risk for bipolar disorder and schizophrenia.
abstract: BACKGROUND
  Recent studies suggest that copy number variation in the human genome is extensive and may play an important role in susceptibility to disease, including neuropsychiatric disorders such as schizophrenia and autism. The possible involvement of copy number variants (CNVs) in bipolar disorder has received little attention to date.
  
  
  OBJECTIVE
  To determine whether large (>100,000 base pairs) and rare (found in <1% of the population) CNVs are associated with susceptibility to bipolar disorder and to compare with findings in schizophrenia.
  
  
  METHODS
  A genome-wide survey of large, rare CNVs in a case-control sample using a high-density microarray.
  
  
  METHODS
  The Wellcome Trust Case Control Consortium.
  
  
  METHODS
  There were 1697 cases of bipolar disorder and 2806 nonpsychiatric controls. All participants were white UK residents.
  
  
  METHODS
  Overall load of CNVs and presence of rare CNVs.
  
  
  RESULTS
  The burden of CNVs in bipolar disorder was not increased compared with controls and was significantly less than in schizophrenia cases. The CNVs previously implicated in the etiology of schizophrenia were not more common in cases with bipolar disorder.
  
  
  CONCLUSIONS
  Schizophrenia and bipolar disorder differ with respect to CNV burden in general and association with specific CNVs in particular. Our data are consistent with the possibility that possession of large, rare deletions may modify the phenotype in those at risk of psychosis: those possessing such events are more likely to be diagnosed as having schizophrenia, and those without them are more likely to be diagnosed as having bipolar disorder.
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff CF14 4XN, Wales, UK.
authors.forename: Detelina
authors.initials: D
authors.lastname: Grozeva
authors.forename: George
authors.initials: G
authors.lastname: Kirov
authors.forename: Dobril
authors.initials: D
authors.lastname: Ivanov
authors.forename: Ian R
authors.initials: IR
authors.lastname: Jones
authors.forename: Lisa
authors.initials: L
authors.lastname: Jones
authors.forename: Elaine K
authors.initials: EK
authors.lastname: Green
authors.forename: David M
authors.initials: DM
authors.lastname: St Clair
authors.forename: Allan H
authors.initials: AH
authors.lastname: Young
authors.forename: Nicol
authors.initials: N
authors.lastname: Ferrier
authors.forename: Anne E
authors.initials: AE
authors.lastname: Farmer
authors.forename: Peter
authors.initials: P
authors.lastname: McGuffin
authors.forename: Peter A
authors.initials: PA
authors.lastname: Holmans
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Owen
authors.forename: Michael C
authors.initials: MC
authors.lastname: O'Donovan
authors.forename: Nick
authors.initials: N
authors.lastname: Craddock
mesh_terms: D001714:Bipolar Disorder / Q000235:genetics*; D056915:DNA Copy Number Variations / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D012307:Risk Factors; D012559:Schizophrenia / Q000235:genetics*