title: Tryptophan hydroxylase 2 gene expression and promoter polymorphisms in bipolar disorder and schizophrenia.
abstract: The tryptophan hydroxylase isoform-2 gene (Tph2) is located on chromosome 12 and is expressed primarily in brain tissue. Although the tryptophan hydroxylase isoform-1 gene (Tph1) has been reported to have a genetic association with bipolar disorder and schizophrenia, the Tph1 isoform is expressed at much lower levels than Tph2 (150-fold less in the mouse brain). We hypothesized that bipolar disorder and schizophrenia are associated with abnormal levels of TPH2 mRNA in the brain. TPH2 and beta-actin mRNA levels in postmortem brain were quantified using real-time PCR. mRNA samples provided by the Stanley Foundation Array Collection were derived from the dorsolateral prefrontal cortex (Brodmann Area 46) of 35 bipolar, 35 schizophrenic, and 35 control subjects. There were significant differences in the mRNA levels among bipolar, schizophrenic, and normal subjects [F(2,102)=3.58; p=0.031]. A greater amount of TPH2 mRNA was found in the bipolar group in comparison with control subjects (Tukey's test: p=0.024). Further investigations of Tph2 are needed to clarify the potential role of this gene in the pathophysiology of bipolar disorder.
authors.affiliation: Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Room 711, 250 College Street, Toronto, ON M5T 1R8, Canada.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Luca
authors.forename: Olga
authors.initials: O
authors.lastname: Likhodi
authors.forename: Hubert H M
authors.initials: HH
authors.lastname: Van Tol
authors.forename: James L
authors.initials: JL
authors.lastname: Kennedy
authors.forename: Albert H C
authors.initials: AH
authors.lastname: Wong
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D012559:Schizophrenia / Q000235:genetics*; D014365:Tryptophan Hydroxylase / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; C494784:TPH2 protein, human; D014365:Tryptophan Hydroxylase