title: Shared polygenic contribution between childhood attention-deficit hyperactivity disorder and adult schizophrenia.
abstract: BACKGROUND
  There is recent evidence of some degree of shared genetic susceptibility between adult schizophrenia and childhood attention-deficit hyperactivity disorder (ADHD) for rare chromosomal variants.
  
  
  OBJECTIVE
  To determine whether there is overlap between common alleles conferring risk of schizophrenia in adults with those that do so for ADHD in children.
  
  
  METHODS
  We used recently published Psychiatric Genome-wide Association Study (GWAS) Consortium (PGC) adult schizophrenia data to define alleles over-represented in people with schizophrenia and tested whether those alleles were more common in 727 children with ADHD than in 2067 controls.
  
  
  RESULTS
  Schizophrenia risk alleles discriminated ADHD cases from controls (P = 1.04 × 10(-4), R(2) = 0.45%); stronger discrimination was given by alleles that were risk alleles for both adult schizophrenia and adult bipolar disorder (also derived from a PGC data-set) (P = 9.98 × 10(-6), R(2) = 0.59%).
  
  
  CONCLUSIONS
  This increasing evidence for a small, but significant, shared genetic susceptibility between adult schizophrenia and childhood ADHD highlights the importance of research work across traditional diagnostic boundaries.
authors.affiliation: Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University School of Medicine, Cardiff, UK.
authors.forename: Marian L
authors.initials: ML
authors.lastname: Hamshere
authors.forename: Evangelia
authors.initials: E
authors.lastname: Stergiakouli
authors.forename: Kate
authors.initials: K
authors.lastname: Langley
authors.forename: Joanna
authors.initials: J
authors.lastname: Martin
authors.forename: Peter
authors.initials: P
authors.lastname: Holmans
authors.forename: Lindsey
authors.initials: L
authors.lastname: Kent
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Owen
authors.forename: Michael
authors.initials: M
authors.lastname: Gill
authors.forename: Anita
authors.initials: A
authors.lastname: Thapar
authors.forename: Mick
authors.initials: M
authors.lastname: O'Donovan
authors.forename: Nick
authors.initials: N
authors.lastname: Craddock
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D020412:Multifactorial Inheritance; D020641:Polymorphism, Single Nucleotide; D012559:Schizophrenia / Q000235:genetics*