title: Magnified effects of the COMT gene on white-matter microstructure in very old age.
abstract: Genetic factors may partly account for between-person differences in brain integrity in old age. Evidence from human and animal studies suggests that the dopaminergic system is implicated in the modulation of white-matter integrity. We investigated whether a genetic variation in the Catechol-O-Methyltransferase (COMT) Val158Met polymorphism, which influences dopamine availability in prefrontal cortex, contributes to interindividual differences in white-matter microstructure, as measured with diffusion-tensor imaging. In a sample of older adults from a population-based study (60-87 years; n = 238), we found that the COMT polymorphism affects white-matter microstructure, indexed by fractional anisotropy and mean diffusivity, of several white-matter tracts in the oldest age group (81-87 years), although there were no reliable associations between COMT and white-matter microstructure in the two younger age groups (60-66 and 72-78 years). These findings extend previous observations of magnified genetic effects on cognition in old age to white-matter integrity.
authors: Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden, goran.papenberg@ki.se.
authors: Goran
authors: G
authors: Papenberg
authors: Martin
authors: M
authors: Lövdén
authors: Erika J
authors: EJ
authors: Laukka
authors: Grégoria
authors: G
authors: Kalpouzos
authors: Lina
authors: L
authors: Keller
authors: Caroline
authors: C
authors: Graff
authors: Ylva
authors: Y
authors: Köhncke
authors: Tie-Qiang
authors: TQ
authors: Li
authors: Laura
authors: L
authors: Fratiglioni
authors: Lars
authors: L
authors: Bäckman
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D003071:Cognition / Q000502:physiology*; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000378:metabolism*; D066127:White Matter / Q000378:metabolism*
chemical_list: C588010:COMT protein, human; D002394:Catechol O-Methyltransferase