title: Association between the DTNBP1 gene and intelligence: a case-control study in young patients with schizophrenia and related disorders and unaffected siblings.
abstract: BACKGROUND
  The dystrobrevin-binding protein 1 (DTNBP1) gene is a susceptibility gene for schizophrenia. There is growing evidence that DTNPB1 contributes to intelligence and cognition. In this study, we investigated association between single nucleotide polymorphisms (SNPs) in the DTNBP1 gene and intellectual functioning in patients with a first episode of schizophrenia or related psychotic disorder (first-episode psychosis, FEP), their healthy siblings, and unrelated controls.
  
  
  METHODS
  From all subjects IQ measurements were obtained (verbal IQ [VIQ], performance IQ [PIQ], and full scale IQ [FSIQ]). Seven SNPs in the DTNBP1 gene were genotyped using single base primer extension and analyzed by matrix-assisted laser deionization mass spectrometry (MALDI-TOF).
  
  
  RESULTS
  Mean VIQ, PIQ, and FSIQ scores differed significantly (p < 0.001) between patients, siblings, and controls. Using a family-based and a case-control design, several single SNPs were significantly associated with IQ scores in patients, siblings, and controls.
  
  
  CONCLUSIONS
  Although preliminary, our results provide evidence for association between the DTNBP1 gene and intelligence in patients with FEP and their unaffected siblings. Genetic variation in the DTNBP1 gene may increase schizophrenia susceptibility by affecting intellectual functioning.
authors: Department of Psychiatry, Academic Medical Center of the University of Amsterdam, The Netherlands. j.r.zinkstok@amc.uva.nl
authors: Janneke R
authors: JR
authors: Zinkstok
authors: Odette
authors: O
authors: de Wilde
authors: Therese A M J
authors: TA
authors: van Amelsvoort
authors: Michael W
authors: MW
authors: Tanck
authors: Frank
authors: F
authors: Baas
authors: Don H
authors: DH
authors: Linszen