title: An interstitial deletion of the long arm of chromosome 21 in a case of a first episode of psychosis.
abstract: OBJECTIVE
  Case of an interstitial deletion of the long arm of chromosome 21 presenting with first episode of psychosis.
  
  
  METHODS
  A case report.
  
  
  RESULTS
  A 16-year-high school student of Somalian origin presented with a first episode of psychosis, mild mental retardation and dysmorphic features. Chromosome analysis revealed an interstitial deletion in the long arm of chromosome 21, described as 46, XX del (21) (q21q22.1).
  
  
  CONCLUSIONS
  First episode of psychosis occurred in combination with neurobiological vulnerability and a complex genetic inheritance. The occurrence of psychosis in our case may be attributable to genes located within the region 21q21q22.1. The possibility that other loci exist on chromosome 21, which predispose to schizophrenia has to be considered. Identification of susceptibility genes will greatly facilitate investigation of factors that contribute to the disease process and may lead to early intervention and prevention.
authors.affiliation: Department of Psychiatry, University of Western Ontario, London Health Sciences Centre, London, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Takhar
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Malla
authors.forename: V
authors.initials: V
authors.lastname: Siu
authors.forename: Colin
authors.initials: C
authors.lastname: MacPherson
authors.forename: Y S
authors.initials: YS
authors.lastname: Fan
authors.forename: L
authors.initials: L
authors.lastname: Townsend
mesh_terms: D000293:Adolescent; D002872:Chromosome Deletion; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics; D011618:Psychotic Disorders / Q000235:genetics*