Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls

Abstract

Introduction: Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease.

Objective: To evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ε2, ε3, ε4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU(rs227959 and rs11136000) in patients with MCI and healthy individuals.

Methodology: We performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics.

Results: We found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend towards poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance.

Discussion: Differences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples.

Keywords: Alzheimer; Alzheimer disease; Cognición; Cognition; Mild cognitive impairment; Neuronorma; Polimorfismos; Polymorphisms; Trastorno neurocognitivo leve.