Genetic variation in human tryptophan hydroxylase 2 (TPH2) influences TPH enzymatic activity and is associated with emotion-related traits and mood disorders.
Findings from psychophysiological and functional imaging studies are indicative of various TPH2 polymorphisms directly influencing serotonergic function and thus impacting on mood disorders and on the response to antidepressant treatment.
Aberrant serotonergic functioning is strongly implicated in hyperphagia in PWS, and females with TPH2 T alleles may be at higher risk for affective or mood disorders.
More comprehensive study of TPH2 genetics is needed to increase the clinical value of the enzyme as a predictor of affective disorder risk and efficacy of antidepressant drugs.