title: Sex modulates the interactive effect of the serotonin transporter gene polymorphism and childhood adversity on hippocampal volume.
abstract: The common genetic variation of the serotonin transporter-linked polymorphic region (5-HTTLPR) has been related to depressive symptoms, in particular after stressful life events. Although it has been investigated in the past, results suggesting that the 5-HTTLPR genotype also affects hippocampal volume are often inconsistent and it remains unclear to what extent reduced hippocampal volume is influenced by the effect of stressful life events and 5-HTTLPR genotype. Moreover, sex, which is known to affect the prevalence of depression substantially, has not been taken into account when trying to disentangle the interactive effect of common genetic variation and environmental stressors on the hippocampus. We investigated this potentially relevant three-way interaction using an automatic magnetic resonance imaging (MRI)-based segmentation of the hippocampus in 357 healthy individuals. We determined the 5-HTTLPR genotype as a biallelic locus and childhood adversity (CA) using a standard questionnaire. An interaction for hippocampal volume was found between the factors sex, genotype, and severe CA (p=0.010) as well as an interaction between genotype and severe CA (p=0.007) in men only. Post hoc tests revealed that only male S'-allele carriers with severe CA had smaller hippocampi (p=0.002). Interestingly, there was no main effect of genotype in men, while female S'-allele carriers had smaller hippocampi than L'L' carriers (p=0.023). Our results indicate that sex modulates the interactive effect of the 5-HTTLPR genotype and CA on hippocampal volume. While the S'-allele is associated with hippocampal volume independent of CA in women, men only have smaller hippocampi if they carry the risk allele and experienced severe CA.
authors.affiliation: Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands. D.Everaerd@donders.ru.nl
authors.forename: Daphne
authors.initials: D
authors.lastname: Everaerd
authors.forename: Lotte
authors.initials: L
authors.lastname: Gerritsen
authors.forename: Mark
authors.initials: M
authors.lastname: Rijpkema
authors.forename: Thomas
authors.initials: T
authors.lastname: Frodl
authors.forename: Iris
authors.initials: I
authors.lastname: van Oostrom
authors.forename: Barbara
authors.initials: B
authors.lastname: Franke
authors.forename: Guillén
authors.initials: G
authors.lastname: Fernández
authors.forename: Indira
authors.initials: I
authors.lastname: Tendolkar
mesh_terms: D000483:Alleles; D001284:Atrophy / Q000235:genetics / Q000473:pathology; D001931:Brain Mapping / Q000379:methods / Q000523:psychology*; D003863:Depression / Q000235:genetics / Q000523:psychology; D005260:Female; D005838:Genotype; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008016:Life Change Events; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology; D008297:Male; D011110:Polymorphism, Genetic; D057566:Self Report; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D012727:Sex Characteristics
chemical_list: D050486:Serotonin Plasma Membrane Transport Proteins