Apolipoprotein E genotype is not associated with cognitive impairment in older adults with bipolar disorder

Author(s)

Kerr, Daniel Shikanai ^{[1, 2]} ; Stella, Florindo ^{[1, 3]} ; Radanovic, Marcia ^[1] ; Aprahamian, Ivan ^[1] ; Ferreira Bertollucci, Paulo Henrique ^[4] ; Forlenza, Orestes Vicente ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Fac Med, Dept & Inst Psychiat, Lab Neurosci LIM 27, Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Ctr Interdisciplinary Res Appl Neurosci NAPNA, Sao Paulo, SP - Brazil

^[3] Univ Estadual Paulista, UNESP, Biosci Inst, Sao Paulo, SP - Brazil

^[4] Univ Fed Sao Paulo, UNIFESP, Dept Neurol & Neurosurg, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: BIPOLAR DISORDERS; v. 18, n. 1, p. 71-77, FEB 2016.
• Web of Science Citations: 5

Abstract

ObjectivesCognitive decline is part of the long-term outcome for many individuals with bipolar disorder (BD). The epsilon 4 allele (APOE{*}4) of apolipoprotein E (APOE) is a well-established risk factor for dementia in Alzheimer's disease (AD). However, its contribution to the risk of cognitive deterioration in BD has not yet been determined. Our aim was to analyze the APOE genotype association with cognitive status in a sample of older adults with BD and compare this to the association in individuals with AD, individuals with mild cognitive impairment (MCI), and healthy controls. MethodsParticipants (n=475) were allocated to four groups: individuals with BD (n=77), those with AD (n=211), those with MCI (n=43), and healthy controls (n=144) according to clinical and neuropsychological assessment. APOE was genotyped by real-time polymerase chain reaction. Tukey's honest significant difference test and Pearson's chi-squared test were used to compare diagnostic groups. ResultsSubjects with BD were similar to controls with respect to the distribution of the APOE genotype (p=0.636) and allele frequencies (p=0.481). Significant differences were found when comparing the AD group to the BD group or to controls (APOE genotype: p<0.0002; allele frequencies: p<0.001). APOE{*}4 was significantly increased in the AD group when compared to the BD group (p=0.031) and controls (p<0.0001). The cognitively impaired BD subgroup (Mini-Mental State Examination below the cutoff score and/or neuropsychological assessment compatible with MCI) had a statistically significant higher frequency of APOE{*}2 compared to the AD group (p=0.003). ConclusionsAPOE{*}4 is not associated with the diagnosis of BD and does not impact the occurrence of dementia in BD. Given the distinct clinical and biological features of cognitive impairment in BD, we hypothesized that dementia in BD is unrelated to AD pathological mechanisms. (AU)

• FAPESP's process: 13/01352-8 - Lithium effect on micro RNA regulation of gene expression on an Alzheimer's Disease model by beta-amyloid induced neurotoxicity in neuronal primary cell culture
• Grantee: Daniel Shikanai Kerr
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/52825-8 - Neurobiology of Alzheimer's disease: risk markers, prognosis and therapeutic response
• Grantee: Wagner Farid Gattaz
• Support Opportunities: Research Projects - Thematic Grants