title: Variants of the CNTNAP2 5' promoter as risk factors for autism spectrum disorders: a genetic and functional approach.
abstract: Contactin-associated protein-like 2 gene (CNTNAP2), a member of the Neurexin gene superfamily, is one of the best-replicated risk genes for autism spectrum disorders (ASD). ASD are predominately genetically determined neurodevelopmental disorders characterized by impairments of language development, social interaction and communication, as well as stereotyped behavior and interests. Although CNTNAP2 expression levels were proposed to alter ASD risk, no study to date has focused on its 5' promoter. Here, we directly sequenced the CNTNAP2 5' promoter region of 236 German families with one child with ASD and detected four novel variants. Furthermore, we genotyped the three most frequent variants (rs150447075, rs34712024, rs71781329) in an additional sample of 356 families and found nominal association of rs34712024G with ASD and rs71781329GCG[7] with language development. The four novel and the three known minor alleles of the identified variants were predicted to alter transcription factor binding sites (TFBS). At the functional level, the respective sequences spanning these seven variants were bound by nuclear factors. In a luciferase promoter assay, the respective minor alleles showed cell line-specific and differentiation stage-dependent effects at the level of promoter activation. The novel potential rare risk-variant M2, a G>A mutation -215 base pairs 5' of the transcriptional start site, significantly reduced promoter efficiency in HEK293T and in undifferentiated and differentiated neuroblastoid SH-SY5Y cells. This variant was transmitted to a patient with autistic disorder. The under-transmitted, protective minor G allele of the common variant rs34712024, in contrast, increased transcriptional activity. These results lead to the conclusion that the pathomechanism of CNTNAP2 promoter variants on ASD risk is mediated by their effect on TFBSs, and thus confirm the hypothesis that a reduced CNTNAP2 level during neuronal development increases liability for ASD.
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: A G
authors.initials: AG
authors.lastname: Chiocchetti
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kopp
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Waltes
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Haslinger
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Duketis
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: T A
authors.initials: TA
authors.lastname: Jarczok
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Poustka
authors.affiliation: Department of Child and Adolescent Psychiatry, Saarland University, Homburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Voran
authors.affiliation: Institute of Experimental Cancer Research in Pediatrics, Frankfurt am Main, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Graab
authors.affiliation: Department of Neurobehavioral Genetics, Institute of Psychobiology, University of Trier, Trier, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Meyer
authors.affiliation: Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: S M
authors.initials: SM
authors.lastname: Klauck
authors.affiliation: Institute of Experimental Cancer Research in Pediatrics, Frankfurt am Main, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Fulda
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JW Goethe University, Frankfurt am Main, Germany.
authors.forename: C M
authors.initials: CM
authors.lastname: Freitag
mesh_terms: D000067877:Autism Spectrum Disorder / Q000235:genetics* / Q000523:psychology; D045744:Cell Line, Tumor; D002648:Child; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D005858:Germany; D057809:HEK293 Cells; D006801:Humans; D007804:Language Development; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D044465:White People / Q000235:genetics
chemical_list: C403049:CNTNAP2 protein, human; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D014157:Transcription Factors