title: Klinefelter syndrome as a window on the aetiology of language and communication impairments in children: the neuroligin-neurexin hypothesis.
abstract: OBJECTIVE
  To compare the phenotype in Klinefelter syndrome (KS) with (i) specific language impairment (SLI) and (ii) XXX and XYY trisomies.
  
  
  METHODS
  Phenotypes of KS, XXX and XYY were based on data from a systematic review of neurodevelopmental outcomes plus a recent parent survey. Phenotype of SLI was based on a published survey of children attending a special school.
  
  
  RESULTS
  There are close similarities between the KS phenotype and SLI. Furthermore, a minority of children with KS have features of autistic spectrum disorder. Similar language and communication problems are seen in the other two sex chromosome trisomies (SCTs), XXX and XYY.
  
  
  CONCLUSIONS
  We propose the neurexin-neuroligin hypothesis, based on the observation that neuroligin genes, which occur on both X and Y chromosomes, are involved in the same synaptic networks as neurexin genes with common variants that affect risk for SLI and autism. According to our hypothesis, the effect of a triple dose of neuroligin gene product will be particularly detrimental when it occurs in conjunction with specific variants of neurexin genes on other chromosomes. This speculative proposal demonstrates the potential of illuminating the aetiology of common neurodevelopmental disorders by studying children with SCTs.
authors.affiliation: Department of Experimental Psychology, University of Oxford, UK. dorothy.bishop@psy.ox.ac.uk
authors.forename: Dorothy V M
authors.initials: DV
authors.lastname: Bishop
authors.forename: Gaia
authors.initials: G
authors.lastname: Scerif
mesh_terms: D002648:Child; D002659:Child Development Disorders, Pervasive / Q000235:genetics; D041321:Chromosomes, Human, X / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D006801:Humans; D007713:Klinefelter Syndrome / Q000235:genetics*; D007806:Language Disorders / Q000235:genetics*; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D019006:Neural Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D012307:Risk Factors; D025064:Sex Chromosome Disorders / Q000235:genetics; D009435:Synaptic Transmission; D014314:Trisomy / Q000235:genetics
chemical_list: D009419:Nerve Tissue Proteins; D019006:Neural Cell Adhesion Molecules