Related Experiment Video
Updated: Jul 14, 2026

Developing a Rat Model for Bipolar Disorder
Published on: May 2, 2025
No association between a TPH2 promoter polymorphism and mood disorders or monoamine turnover
J John Mann1, Dianne Currier, Lauren Murphy
1Department of Neuroscience, New York State Psychiatric Institute, NY 10032, USA. jjm@columbia.edu
Background:
Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in serotonin synthesis. TPH2 is a recently discovered isoform that is expressed predominantly in serotonin neurons. Associations are reported of TPH2 polymorphisms with MDD, bipolar disorder and suicidal behavior. This study examines a single nucleotide polymorphism in the putative promoter region of the TPH2 gene.
Methods:
One hundred nine bipolar, 324 major depressive disorder, and 130 healthy volunteers were genotyped for the rs4131347 (-C8347G) promoter SNP. Association was assessed with diagnosis, suicide attempt status, severity of psychopathology and cerebrospinal fluid monoamine metabolite levels of 5-HIAA, HVA, and MHPG. General linear models and logistic regression tested the effect of genotype*childhood abuse interactions on psychopathology severity and suicide attempt.
Results:
There was no association between genotype and either mood disorder, suicide attempt status, psychopathology severity or CSF monoamine metabolite levels.
Conclusions:
No association was detected between the rs4131347 (-C8347G) SNP in the promoter region of the TPH2 gene and mood disorders, suicidal behavior or monoamine function.
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Bipolar Disorder

