The importance of TCF4 gene in the etiology of recurrent depressive disorders

Background: A recurrent depressive disorder is one of the most commonly diagnosed disease entities among psychiatric disorders. The prevalence and morbidity of depression are constantly increasing. Numerous studies have demonstrated the role of genetic factors in the etiology of depressive disorders. Many studies are being conducted to identify genes that predispose to depression. The purpose of this study was to investigate the role of TCF4 gene in the etiology of recurrent depressive disorders and, in particular, to assess expression of the TCF4 gene at the mRNA and protein level in patients with recurrent depressive disorders versus healthy individuals. Material and methods: The examined population consisted of 170 individuals suffering from depression and 90 healthy individuals. The expressions of the TCF4 gene at the mRNA and protein level were assessed. Results: Decreased TCF4 expression at the mRNA and protein level was found in patients with depressive disorder versus healthy individuals. Expression of the studied gene was not affected by the patients' sex and age. The statistical analysis also showed no correlation between the expression of TCF4 at the mRNA and protein level and the number of episodes or the severity of symptoms. Among the clinical manifestations of depression, only the duration of the illness correlated with the expression of TCF4 at the mRNA level. Conclusions: Expression of TCF4 at the mRNA and protein level may be significant in the pathomechanism of recurrent depressive disorder and it is not dependent on sex and age.