title: CAG repeat polymorphisms in KCNN3 (HSKCa3) and PPP2R2B show no association or linkage to schizophrenia.
abstract: The purpose of this study was to determine whether genetic linkage or association could be observed between schizophrenia (SZ) and the CAG repeat polymorphisms within the genes KCNN3 (known previously as hSKCa3) and PPP2R2B (linked to Spino-Cerebellar Atrophy 12) in the Xhosa population in South Africa. Neither locus has been studied previously in African populations. The polymorphisms were genotyped in 589 individuals to form samples for Transmission Disequilibrium Test (TDT) analysis (176 unrelated probands, 145 with both parents and 30 with one parent genotyped), linkage analysis (49 families with 54 independent affected sib pairs [ASPs]), and case-control analyses (67 familial cases with a first-degree SZ relative, 101 sporadic cases with no affected first- or second-degree relative, and 90 control cases). No significant differences were found among familial cases, sporadic cases and controls in allele sizes (Kruskal-Wallis tests) or the numbers of alleles with sizes above and below the mean size for each polymorphism. Allele size was not correlated with age of onset (Spearman correlation). No significant evidence for association was observed using TDT analyses for all triads and separately for the familial triads. No significant evidence for linkage was observed for either locus with affected sib pair analysis using the possible triangle method or with Non-Parametric Linkage (NPL) analysis of the multiplex families. In conclusion, no significant evidence for linkage or association with SZ was observed for either polymorphism in this population.
authors.affiliation: LGN-CNRS UMR 7091, Bâtiment CERVI, Hôpital de la Pitié-Salpêtrière, Paris, France.
authors.forename: Claudine
authors.initials: C
authors.lastname: Laurent
authors.forename: Dana
authors.initials: D
authors.lastname: Niehaus
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bauché
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Levinson
authors.forename: Stéphane
authors.initials: S
authors.lastname: Soubigou
authors.forename: Simon
authors.initials: S
authors.lastname: Pimstone
authors.forename: Michael
authors.initials: M
authors.lastname: Hayden
authors.forename: Irena
authors.initials: I
authors.lastname: Mbanga
authors.forename: Robin
authors.initials: R
authors.lastname: Emsley
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Deleuze
authors.forename: Jacques
authors.initials: J
authors.lastname: Mallet
mesh_terms: D016022:Case-Control Studies; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D005192:Family Health; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D011110:Polymorphism, Genetic; D015221:Potassium Channels / Q000235:genetics*; D024681:Potassium Channels, Calcium-Activated; D012559:Schizophrenia / Q000235:genetics*; D051640:Small-Conductance Calcium-Activated Potassium Channels; D020754:Spinocerebellar Ataxias / Q000235:genetics*; D018911:Trinucleotide Repeats / Q000235:genetics*
chemical_list: C406328:KCNN3 protein, human; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D051640:Small-Conductance Calcium-Activated Potassium Channels; D004247:DNA