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P1‐051: Fok1 vitamin d receptor gene polymorphisms and association with cognition
Author(s) -
Pettersen Jacqueline A.,
Fok Alice C.,
Robin Hsiung Ging-Yuek
Publication year - 2015
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2015.06.248
Subject(s) - single nucleotide polymorphism , cognition , medicine , genotyping , genetics , genotype , psychology , biology , gene , psychiatry
Background:Vitamin D insufficiency has been associated with Alzheimer’s disease (AD) and impaired cognition. Recent studies have also shown significant associations between vitamin D receptor (VDR) single nucleotide polymorphisms (SNPs), AD and cognitive decline. While Fok1 SNPs have not been directly implicated in AD, the TaubF haplotype (combined polymorphisms in Taq1, Apa1, Tru91, Bsm1,Fok1) has been. A recent study also revealed a significant association between Fok1 and global cognition. We hypothesized that executive functioningwould differ among Fok1 SNPs and sought to examine the relationship between Fok1 genotype, vitamin D level, and cognitive functioning. Methods: Participants (n1⁄478) were healthy adults living at a northern latitude (54N) assessed in winter months for serum vitamin D (25OHD) levels and underwent cognitive testing with the Symbol Digits Modalities Test, verbal (phonemic) fluency, digit span and CANTAB battery, including a spatial working memory (SWM) task. Genotyping for Fok1 (rs2228570) was done by TaqMan assay (ABI3700). Results:Prevalence of Fok1 SNPs (AA, AG, GG) were in approximate Hardy Weinberg Equilibrium. Vitamin D levels, age, and sex did not differ significantly but years of education (YOE) was higher in the GG (16.864) versus AG (14.263) groups (p1⁄4.022). Therewas a significant difference among SNPs on both strategy, AA1⁄428.368, AG1⁄434.566, GG1⁄432.567; F(2,75)1⁄43.18, p1⁄4.047 and error measures, AA1⁄415.4616, 34.3617, 28.2619; F(2,75)1⁄43.54, p1⁄4.034, of the SWM task, a test of nonverbal executive functioning. In particular, the AA group performed best and significantly better than the AG group (Bonferroni p’s <.05). Results did not change with correction for YOE. There were no significant differences among SNPs on any of the other cognitive tests. Conclusions:Polymorphisms in the Fok1 VDR gene may contribute to differences in cognitive function, independently of vitamin D level and YOE. In particular, the SWM task differentiated between genotypes on two measures. This same task has previously been shown to differentiate between individuals with insufficient and sufficient levels of vitaminD.Our findings add to existing literature that Fok1 polymorphisms are associated with nonverbal executive task performance in addition to global cognition. Given our small sample size, these preliminary results necessitate confirmation in a larger study.