Psychological Medicine

Original Articles

The BDNF Val66Met polymorphism impacts parahippocampal and amygdala volume in healthy humans: incremental support for a genetic risk factor for depression

C. Montaga1 c1, B. Webera2a3, K. Fliessbacha2a3, C. Elgera2a3 and M. Reutera1

a1 Department of Psychology, Laboratory of Neurogenetics, University of Bonn, Germany

a2 Department of Epileptology, University Hospital of Bonn, Germany

a3 Department for NeuroCognition, Life and Brain Centre, Bonn, Germany

Abstract

Background The role of the brain-derived neurotrophic factor (BDNF) in the pathogenesis of affective disorders such as depression has been controversial. Mounting evidence comes from structural imaging, that the functional BDNF Val66Met polymorphism influences the hippocampal volume with carriers of the 66Met allele (Val/Met and Met/Met group) having smaller hippocampi. Given that stress-induced atrophy of the hippocampus is associated with the pathogenesis of affective disorders, the functional BDNF Val66Met polymorphism could be an incremental risk factor.

Method Eighty-seven healthy Caucasian participants underwent structural imaging and were genotyped for the BDNF Val66Met polymorphism. Data were analysed by means of voxel-based morphometry (VBM).

Results Region of interest (ROI) analyses revealed an association between the 66Met allele and smaller parahippocampal volumes and a smaller right amygdala. In addition, the whole-brain analysis showed that the thalamus, fusiformus gyrus and several parts of the frontal gyrus were smaller in 66Met allele carriers.

Conclusions This study demonstrates that the impact of the BDNF Val66Met polymorphism is not confined to the hippocampus but also extends to the parahippocampal gyrus and the amygdala.

(Received August 21 2008)

(Revised January 29 2009)

(Accepted February 10 2009)

(Online publication April 01 2009)

Correspondence

c1 Address for correspondence: Dr C. Montag, University of Bonn, Department of Psychology, Kaiser-Karl-Ring 9, D-53111 Bonn, Germany. (Email: christian.montag@uni-bonn-diff.de)

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