Study Report

CitationGizatullin R, 2008 PubMed
Full InfoGizatullin R, Zaboli G, Jonsson EG, Asberg M, Leopardi R. The tryptophan hydroxylase (TPH) 2 gene unlike TPH-1 exhibits no association with stress-induced depression. Journal of affective disorders 2008; 107(1-3): 175-179.

Hypothesis or Background Serotonin (5-HT) has been implicated in the pathophysiology of several psychiatric disorders including major depression (MD). Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the biosynthesis of serotonin (5-HT), and might be related to the pathogenesis of MD. Two isoforms are known, TPH-1 and TPH-2. Their association with MD is still debated.
Sample Information194 patients with stress-induced MD, and 246 healthy controls
Method DetailA case-control design was used for candidate gene-disease association in 194 patients with stress-induced MD, and 246 healthy controls, all North European Caucasians. Five TPH-2 polymorphisms were analyzed in terms of genotype, allele, and haplotype-based associations.
Method Keywordsgenotyping
ResultNeither single marker nor haplotype-based analyses showed significant associations between TPH-2 and MD.
ConclusionsThere was no association between TPH-2 gene variants and MD in the same population that had shown a strong association with TPH-1. Hence, the results suggest that in this particular group of stress-induced depression patients TPH-1 appears to be more relevant to MD pathogenesis than TPH-2.

Relationships reported by Gizatullin R, 2008