title: Effects of a Polymorphism of the Neuronal Amino Acid Transporter SLC6A15 Gene on Structural Integrity of White Matter Tracts in Major Depressive Disorder.
abstract: BACKGROUND
  The SLC6A15 gene has been identified as a novel candidate gene for major depressive disorder (MDD). It is presumed to be involved in the pathophysiology of MDD through regulation of glutamate transmission in the brain. However, the involvement of this gene in microstructural changes in white matter (WM) tracts remains unclear. We aimed to investigate the influence of a polymorphism of this gene (rs1545853) on the structural integrity of WM tracts in the cortico-limbic network.
  
  
  METHODS
  Eighty-six patients with MDD and 64 healthy controls underwent T1-weighted structural magnetic resonance imaging, including diffusion tensor imaging (DTI), and genotype analysis. We selected the genu of the corpus callosum, the uncinate fasciculus, cingulum, and fornix as regions of interest, and extracted fractional anisotropy (FA) values using the FMRIB Diffusion Toolbox software.
  
  
  RESULTS
  FA values for the left parahippocampal cingulum (PHC) was significantly reduced in the patients with MDD compared to healthy control participants (p = 0.004). We also found that MDD patients with the A allele showed reduced FA values for the left PHC than did healthy controls with the A allele (p = 0.012). There was no significant difference in the FA value of left PHC for the comparison between the G homozygotes of MDD and healthy control group.
  
  
  CONCLUSIONS
  We observed an association between the risk allele of the SLC6A15 gene rs1545843 and the WM integrity of the PHC in MDD patients, which is known to play an important role in the neural circuit involved in emotion processing.
authors.affiliation: Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea.
authors.forename: Sunyoung
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyu-Man
authors.initials: KM
authors.lastname: Han
authors.affiliation: Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea.
authors.forename: June
authors.initials: J
authors.lastname: Kang
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eunsoo
authors.initials: E
authors.lastname: Won
authors.affiliation: Department of Medical Bioscience, Graduate school, Soonchunhyang University, Bucheon, South Korea.
authors.forename: Hun Soo
authors.initials: HS
authors.lastname: Chang
authors.affiliation: Brain Convergence Research Center, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Woo Suk
authors.initials: WS
authors.lastname: Tae
authors.affiliation: Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyu Ri
authors.initials: KR
authors.lastname: Son
authors.affiliation: Department of Emergency Medicine, College of Medicine, Korea University, Seoul, Republic of Korea.
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea.|Brain Convergence Research Center, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Ham
mesh_terms: D000328:Adult; D000483:Alleles; D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics*; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging* / Q000201:enzymology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D066127:White Matter / Q000000981:diagnostic imaging* / Q000201:enzymology
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D009419:Nerve Tissue Proteins; C506212:SLC6A15 protein, human