Objective: The apolipoprotein E (ApoE) Ε4 allele is a well-documented genetic risk factor for Alzheimer’s disease (AD). Its role, if any, in the progression of cognitive and functional impairment in AD has been the subject of discrepant reports in the literature. This study aimed to determine whether ApoE Ε4 dose is related to the progression of cognitive and functional decline in AD patients by combined retrospective and prospective analyses. Methods: A sample of 366 AD patients was genotyped for ApoE. Subjects received tests of cognition (Mini-Mental State Examination, MMSE; Alzheimer’s Disease Assessment Scale-Cognitive subscale, ADAS-Cog) and daily function (Instrumental Activities of Daily Living, IADL; Alzheimer’s Disease Cooperative Study-Activities of Daily Living, ADCS-ADL) at baseline and at multiple subsequent time points during their participation in a variety of research protocols. In retrospective analyses, scores on baseline cognitive and functional measures were compared cross-sectionally among genotype groups, controlling for duration of symptoms. In prospective analyses, longitudinal rates of change for each measure were computed by linear regression and compared across genotype groups. Results: No association was observed between ApoE Ε4 dose and any of the retrospective or prospective measures of cognitive or functional decline in this AD patient sample. Conclusions: Although ApoE Ε4 increases the risk for AD and decreases the age of disease onset in population studies, it did not significantly influence the rate of disease progression in cognitive or functional domains in our sample.

The apolipoprotein E (ApoE) e4 allele is a well-documented genetic risk factor for sporadic Alzheimer's disease (AD). Its association with psychopathology among AD patients has been the subject of discrepant reports. We aimed to determine whether ApoE e4 + and e4-AD patients exhibit a different risk profile for psychotic symptoms and other behavioral disturbances. The Neuropsychiatric Inventory (NPI) was administered to determine the frequency and severity of psychotic and other behavioral symptoms in a sample of n ¼ 266 AD patients who had been genotyped for ApoE. Multiple logistic regression models were used to calculate the association between the ApoE e4 allele and the presence of psychotic symptoms (delusions or hallucinations). Exploratory analyses were also conducted to determine the impact of disease severity on e4 effects and to examine the association between e4 and other behavioral symptoms. ApoE e4 was significantly associated with psychotic symptoms (odds ratio (OR) ¼ 1.87, 95% CI ¼ 1.07-3.29, P ¼ 0.029), adjusting for age, sex, education, and MMSE score. More stringent definitions of clinically significant psychosis yielded similar results. Exploratory analyses suggested that this effect accrued specifically from patients with severe-stage AD and primarily from an association between e4 and delusions. The e4 allele did not appear to influence the development of most other behavioral symptoms in our sample. In conclusion, AD patients who carry the ApoE e4 allele are at greater risk than noncarriers for developing psychotic symptoms, particularly as the severity of their dementia progresses.

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that promotes neuronal survival, growth, and differentiation. The role of BDNF in learning and memory suggests that it may also modulate the clinical course of Alzheimer's disease (AD). This study aimed to determine whether BDNF genetic variants are related to premorbid educational attainment, progression of cognitive and functional decline, and associated neuropsychiatric symptoms in AD patients. A sample of AD subjects (N = 341) was genotyped for the BDNF polymorphisms: Val66Met, C270T, and G-712A. Subjects received tests of cognition and daily function at baseline and at multiple subsequent time points. They were also characterized for the frequency and severity of neuropsychiatric symptoms. There was a significant effect of Val66Met genotype on educational attainment (F = 7.49, df = 2,329, P = 0.00066), with Met/Met homozygotes having significantly lower education than both the Val/Met and Val/Val groups. No association was observed between any BDNF polymorphism and measures of cognitive or functional decline. The T-allele of the C270T polymorphism was associated with a higher prevalence of neuropsychiatric symptoms and specifically with the presence of hallucinations. The effect of the Val66Met polymorphism on premorbid educational attainment is intriguing and should be verified in a larger sample.