Identification of PIK3C3 promoter variant associated with bipolar disorder and schizophrenia.
BACKGROUND
Genes involved in phosphoinositide (PI) lipid metabolism are excellent candidates to consider in the pathogenesis of bipolar disorder (BD) and schizophrenia (SZ). One is PIK3C3, a member of the phosphatidylinositide 3-kinase family that maps closely to markers on 18q linked to both BD and SZ in a few studies.


METHODS
The promoter region of PIK3C3 was analyzed for mutations by single-strand conformation polymorphism analysis and sequencing. A case-control association study was conducted to determine the distribution of variant alleles in unrelated patients from three cohorts. Electromobility gel shift assays (EMSA) were performed to assess the functional significance of variants.


RESULTS
Two polymorphisms in complete linked disequilibrium with each other were identified, -432C- > T and a "C" insert at position -86. The -432T allele occurs within an octamer containing an ATTT motif resembling members of the POU family of transcription factors. In each population analyzed, an increase in -432T was found in patients. EMSAs showed that a -432T containing oligonucleotide binds to brain proteins that do not recognize -432C.


CONCLUSIONS
A promoter mutation in a PI regulator affecting the binding of a POU-type transcription factor may be involved in BD and SZ in a subset of patients.
Stopkova
Pavla
P
Psychiatric Clinic, First Medical Faculty, Charles University, Prague, Czech Republic.
Saito
Takuya
T
Papolos
Demitri F
DF
Vevera
Jan
J
Paclt
Ivo
I
Zukov
Ilja
I
Bersson
Yonina B
YB
Margolis
Benjamin A
BA
Strous
Rael D
RD
Lachman
Herbert M
HM
D000483:Alleles; D000818:Animals; D001714:Bipolar Disorder / Q000150:complications / Q000235:genetics*; D001921:Brain / Q000378:metabolism; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015331:Cohort Studies; D016384:Consensus Sequence; D004252:DNA Mutational Analysis / Q000379:methods; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D014644:Genetic Variation; D005838:Genotype; D006321:Heart; D006801:Humans; D007668:Kidney; D015810:Linkage Disequilibrium; D008099:Liver; D051379:Mice; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D018807:Polymorphism, Single-Stranded Conformational; D011401:Promoter Regions, Genetic; D012559:Schizophrenia / Q000150:complications / Q000235:genetics*
D019869:Phosphatidylinositol 3-Kinases