The International Journal of Neuropsychopharmacology

Gene expression of tryptophan hydroxylase 2 in post-mortem brain of suicide subjects

Vincenzo De Luca a1, Olga Likhodi a1, Hubert H. M. Van Tol a1, James L. Kennedy a1 and Albert H. C. Wong a1c1
a1 Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada

Article author query
luca vd   [PubMed][Google Scholar] 
likhodi o   [PubMed][Google Scholar] 
van tol hh   [PubMed][Google Scholar] 
kennedy jl   [PubMed][Google Scholar] 
wong ah   [PubMed][Google Scholar] 


The tryptophan hydroxylase isoform-2 gene (TPH2) is located on chromosome 12 and is expressed primarily in brain tissue. While genetic association and mRNA expression studies implicate the tryptophan hydroxylase isoform-1 gene (TPH1) in depression and suicidality, the TPH1 gene is 150-fold less expressed in mouse brain than TPH2. We hypothesized that completed suicide is associated with abnormal TPH2 expression in the brain. TPH2 and β-actin mRNA levels were measured in post-mortem brain using quantitative real-time PCR. mRNA samples provided by the Stanley Foundation Array Collection were derived from the dorsolateral prefrontal cortex (Brodmann Area 46) of 23 completed suicides and 23 control subjects. There is no difference in the mRNA levels between the suicide group and non-suicide group (p=0.69). Although greater amounts of TPH2 mRNA were found in the suicide group, this difference was not significant. Further investigation of TPH2 gene expression is needed to clarify the potential role of this gene in the pathophysiology of suicide.

(Published Online June 8 2005)
(Received November 11 2004)
(Reviewed February 6 2005)
(Revised February 28 2005)
(Accepted March 9 2005)

Key Words: Brain; expression; mRNA; post-mortem; RT–PCR; suicide; TPH2.

c1 Centre for Addiction and Mental Health, 250 College Street, Room 711, Toronto, Ontario, Canada, M5T 1R8. Tel.: +416 535-8501 (ext. 4010) Fax: +416 979 4663 E-mail:

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