Dataset Information

KIBRA genetic polymorphism influences episodic memory in later life, but does not increase the risk of mild cognitive impairment.

ABSTRACT: A common T-->C polymorphism of the KIBRA gene has been recently associated with worse performance on tests of episodic memory. This should aimed to determine whether older adults with the KIBRA CC genotype (1) have worse episodic memory than T-allele carriers and, (2) are more likely to express the phenotype of amnestic mild cognitive impairment (MCI). Our Cross-sectional investigation of 312 adults aged 50-89 years free of dementia included genotyping of the KIBRA rs17070145 gene and the assessment of episodic memory to Establish a Registry for Alzheimer's Disease (CERAD). Participants were considered to have MCI if their memory scores were 1.5 standard deviations below the mean norm for the population. 138/312 participants carried the KIBRA CC genotype. Their immediate and delayed recall scores were significantly lower than the scores of carriers of the T allele (P < 0.05; adjusted for age, gender and pre-morbid IQ), although the effect size of the CC genotype was weak (0.2). Amongst our volunteers, 133 had MCI, of whom 63 (47.4%) had the CC genotype. There was no association between KIBRA genotype and MCI phenotype (TT/CT versus CC; adjusted odds ratio = 1.70, 95%CI = 0.74, 3.90). We concluded that the KIBRA T-->C polymorphism contributes to modulate episodic memory amongst community-dwelling older adults free of dementia, but plays no obvious role in the phenotypic expression of MCI. Future studies should aim to clarify the long term implications of this polymorphism on cognitive function and to identify other genes involved in the modulation of memory that might confer greater risk of MCI in later life.

SUBMITTER: Almeida OP

PROVIDER: S-EPMC3918083 | biostudies-literature | 2008 Sep-Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

KIBRA genetic polymorphism influences episodic memory in later life, but does not increase the risk of mild cognitive impairment.

Almeida O P OP Schwab S G SG Lautenschlager N T NT Morar B B Greenop K R KR Flicker L L Wildenauer D D

Journal of cellular and molecular medicine 20080111 5A

A common T-->C polymorphism of the KIBRA gene has been recently associated with worse performance on tests of episodic memory. This should aimed to determine whether older adults with the KIBRA CC genotype (1) have worse episodic memory than T-allele carriers and, (2) are more likely to express the phenotype of amnestic mild cognitive impairment (MCI). Our Cross-sectional investigation of 312 adults aged 50-89 years free of dementia included genotyping of the KIBRA rs17070145 gene and the assess ...[more]

PMID: 18194457

Similar Datasets

Project description:IntroductionLoss of awareness is a common symptom in Alzheimer's Disease (AD) and responsible for a significant loss of functional abilities. The mechanisms underlying loss of awareness in AD is unknown, although previous findings have implicated dysfunction of primary executive functioning (EF) or episodic memory (EM) to be the cause. Therefore, our main study objective was to explore the involvement of EF and EM dysfunction in amyloid-related loss of awareness across the clinical spectrum of AD.MethodsA total of 895 participants (362 clinically normal [CN], 422 people with mild cognitive impairment [MCI] and 111 with dementia) from the Alzheimer's Disease Neuroimaging Initiative were used for the analyses. A sub-analysis was performed in 202 participants who progressed in their clinical diagnosis from CN to MCI or MCI to dementia as well as dementia patients. Mediation models were used in each clinical group with awareness (assessed with the Everyday Cognitive function questionnaire) as a dependent variable to determine whether EF and/or EM would mediate the effect of amyloid on awareness. We also ran these analyses with subjective and informant complaints as dependent variables. Direct correlations between all variables were also performed.ResultsWe found evidence for a decline in awareness across the groups, with increased awareness observed in the CN group and decreased awareness observed in the MCI and dementia groups. Our results showed that EM, and not EF, partially mediated the relationship between amyloid and awareness such that greater amyloid and lower EM performance was associated with lower awareness. When analyzing each group separately, this finding was only observed in the MCI group and in the group containing progressors and dementia patients. When repeating the analyses for subjective and informant complaints separately, the results were replicated only for the informant's complaints.DiscussionOur results demonstrate that decline in EM and, to a lesser degree, EF, mediate the effect of amyloid on awareness. In line with previous studies demonstrating the development of anosognosia in the prodromal stage, our findings suggest that decreased awareness is the result of an inability for the participant to update his/her insight into his/her cognitive performance (i.e., demonstrating a petrified self).

Dataset Information

KIBRA genetic polymorphism influences episodic memory in later life, but does not increase the risk of mild cognitive impairment.

Publications

KIBRA genetic polymorphism influences episodic memory in later life, but does not increase the risk of mild cognitive impairment.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets