title: Substantial genetic link between IQ and working memory: implications for molecular genetic studies on schizophrenia. the European twin study of schizophrenia (EUTwinsS).
abstract: While evidence is accumulating to support specific neurocognitive deficits as putative endophenotypes for schizophrenia, the heritability of these deficits in healthy subjects and whether they share common genetic influences, is not well established. In the present study, 529 healthy adult twins from two centers within the European Twin Study Network on Schizophrenia (EUTwinsS) were assessed on two domains that are consistently found to be particularly compromised in schizophrenia. Specifically, Intellectual Quotient Score (IQ) and the Letter-Number Sequencing Test (LNS), a measure of working memory, were measured in all twins. Latent variable components were explored through structural equation modeling, and common genetic underpinnings were examined using bivariate analyses. Results showed that the phenotypic correlation between IQ and working memory was almost entirely attributed to shared genetic variance (95.5%). We discuss the potential use of a combined measure of IQ and working memory to improve the power of molecular studies in detecting the genetic mechanisms underlying schizophrenia.
authors: Unitat d'Antropologia, Departament de Biologia Animal, Facultat de Biologia, Universitat de Barcelona, Institut de Biomedicina de la Universitat de Barcelona IBUB, Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Barcelona, Spain. xgoldberg@ub.edu
authors: Ximena
authors: X
authors: Goldberg
authors: Silvia
authors: S
authors: Alemany
authors: Araceli
authors: A
authors: Rosa
authors: Marco
authors: M
authors: Picchioni
authors: Igor
authors: I
authors: Nenadic
authors: Sheena F
authors: SF
authors: Owens
authors: Fruhling
authors: F
authors: Rijsdijk
authors: Irene
authors: I
authors: Rebollo
authors: Heinrich
authors: H
authors: Sauer
authors: Robin M
authors: RM
authors: Murray
authors: Lourdes
authors: L
authors: Fañanás
authors: Timothea
authors: T
authors: Toulopoulou
mesh_terms: D000328:Adult; D003071:Cognition; D005060:Europe; D005260:Female; D006801:Humans; D007360:Intelligence / Q000235:genetics*; D008297:Male; D008568:Memory; D008875:Middle Aged; D012559:Schizophrenia / Q000235:genetics*