No association of the Val66Met polymorphism of the brain-derived neurotrophic factor with hippocampal volume in major depression

Abstract

Recently, an association of the Val66Met polymorphism of the brain-derived neurotrophic factor with hippocampal volume in patients with major depression has been reported. Here, we aimed at replicating this finding in an independent German sample. We included 79 patients with unipolar major depressive episodes and 84 healthy comparison participants. The brain-derived neurotrophic factor Val66Met polymorphism was determined in all participants. The volume of the hippocampus was manually traced on high-resolution magnetic resonance images. The hippocampal volumes of patients were significantly smaller than those of the comparison participants, confirming previous reports. There was, however, no Val66Met effect on hippocampal volume in either group. To conclude, we did not replicate the Val66Met effect on hippocampal volume in neither patients with major depression nor in healthy participants.

Reduced hippocampal volumes in healthy carriers of brain-derived neurotrophic factor Val66Met polymorphism: Meta-analysis

“…These methods are optimal and sufficient for volumetry of the hippocampus. Exclusion of the only study which used a 3-T scanner (Jessen et al 2009) or 2 mm slice thickness (Gonul et al 2011) in the sensitivity analysis did not change the results. Furthermore it has been shown that slice thickness does not affect hippocampal volumes (Campbell et al 2004).…”

“…Out of 126 studies initially found by the systematic search, 14 studies measured hippocampal volumes in healthy subjects genotyped for BDNF gene Val66Met polymorphism (Szeszko et al 2005;Agartz et al 2006;Bueller et al 2006;Frodl et al 2007;Takahashi et al 2008b;Chepenik et al 2009;Dutt et al 2009;Jessen et al 2009;Joffe et al 2009;Koolschijn et al 2010;Benjamin et al 2010;Gonul et al 2011;Haukvik et al 2010;Karnik et al 2010). The study by (Haukvik et al 2010) overlapped with the (Agartz et al 2006) study, thus yielding 13 non-overlaping datasets.…”

“…Two additional volumetric studies provided data only on a mixture of healthy controls and patients without separating the results (Szeszko et al 2005;Benjamin et al 2010). Seven of the studies thus met inclusion criteria for this meta-analysis (Bueller et al 2006;Frodl et al 2007;Takahashi et al 2008b;Dutt et al 2009;Jessen et al 2009;Koolschijn et al 2010;Gonul et al 2011). The study by (Dutt et al 2009) included four subjects with personal history of depression.…”

“…In six out of seven studies included in the meta-analysis the BDNF Val66Met genotype distributions were in Hardy-Weinberg equilibrium (results directly provided: Frodl et al 2007;Takahashi et al 2008b;Dutt et al 2009;Koolschijn et al 2010), results calculated from genotype frequencies (Bueller et al 2006;Gonul et al 2011). A single study did not provide information on HWE or sufficient details to calculate it (Jessen et al 2009). Slice thickness in the meta-analyzed studies ranged from 1 to 2 mm, with magnet field strength of 1.5 T in all studies with exception of 3 T magnet in Jessen et al (2009), please see Table I for details.…”

“…A single study did not provide information on HWE or sufficient details to calculate it (Jessen et al 2009). Slice thickness in the meta-analyzed studies ranged from 1 to 2 mm, with magnet field strength of 1.5 T in all studies with exception of 3 T magnet in Jessen et al (2009), please see Table I for details.…”