Neurochemical diagnosis of Alzheimer's dementia by CSF Abeta42, Abeta42/Abeta40 ratio and total tau

Cerebrospinal fluid (CSF) concentrations of amyloid beta peptides ending at positions 42 and 40 (Abeta42 and Abeta40, respectively), and total tau (tTau) protein were measured by ELISA in order to compare their accuracy in discriminating patients with Alzheimer's disease (AD, n = 22), non-Alzheimer dementia (nAD, n = 11) and control subjects (CON, n=35). As compared to the other groups, the concentrations of Abeta42 and tTau were decreased (P<0.001) and increased (P<0.001) in AD, respectively, while Abeta40 did not differ significantly among the groups. Receiver operating characteristic (ROC) analysis was performed to define cut-off values for maximized sensitivity and specificity. For all groups compared the Abeta peptide ratio 42/40 classified more patients correctly, as compared to the concentration of Abeta42 alone: AD versus controls, 94 and 86.7%; AD versus nAD, 90 and 85% and AD versus nAD plus controls, 90.8 and 87%, respectively. The percentage of correctly classified patients was further improved when the Abeta ratio was combined with the analysis of the tTau concentration. Presence of the apolipoprotein E 4 allele, age or degree of mental disability did not significantly influence the parameters studied.     

Cerebral glucose metabolism,cerebrospinal fluid-beta-amyloid1-42 (CSF-Abeta42), tau and apolipoprotein E genotype in long-term rivastigmine and tacrine treated Alzheimer disease (AD) patients

We evaluated cerebral glucose metabolism (CMRglc) and cerebrospinal fluid (CSF) levels of tau and beta-amyloid(1-42) (Abeta42), in relation to apolipoprotein E (ApoE) genotype, in patients with mild Alzheimer disease (AD) treated with rivastigmine (n=11) and tacrine (n=16) for 1 year; and two untreated AD groups. The rivastigmine-treated AD patients showed a significant increase in CMRglc as compared to both tacrine-treated and untreated AD subjects. The rivastigmine-treated AD group showed no change in CSF-tau levels after 1 year, while in contrast a significant increase as seen in tacrine-treated and untreated AD patients. The CSF-tau changes were mainly seen in ApoE epsilon4 carriers. There was no significant change in Abeta42 after 1-year treatment with either rivastigmine or tacrine. This study shows that the two long-term cholinesterase inhibitor treatments exert different effects on biological markers for AD.     

TNF polymorphisms in Alzheimer disease and functional implications on CSF beta-amyloid levels

Alzheimer disease (AD), vascular dementia, and stroke are all associated with inflammation though their respective initiating factors differ. Recently a polymorphism in the proinflammatory cytokine tumor necrosis factor (TNF), in association with apolipoprotein E (APOE), was reported to increase AD risk. Two SNPs, rs1799724 (-850C>T; NT_007592.14:g.22400733C>T) and rs1800629 (-308G>A; [NT_007592.14:g.22401282G>A]), and the APOE polymorphism were genotyped in 506 patients with sporadic AD and in 277 cognitively healthy controls. In a subset of 90 individuals we also investigated whether these SNPs exerted any functional effects on cerebrospinal fluid (CSF) beta-amyloid (Abeta) levels. The frequency of the rs1799724 genotypes and the rs1799724-T allele were significantly different in AD individuals (P=0.009; odds ratio [OR], 1.63; 95% confidence interval [CI], 1.13-2.34), while the rs1800629 SNP was not associated with AD. Significant interaction was observed between the rs1799724-T and APOE epsilon4 alleles in that the rs1799724-T allele significantly modified risk associated with possession of the epsilon4 allele only (epsilon4 in absence of rs1799724-T: OR, 2.92; 95% CI, 2.00-4.27; epsilon4 in presence of rs1799724-T: OR, 6.65; 95% CI, 3.26-13.55; P=0.03). Haplotyping analysis revealed a significant overrepresentation of an rs1799724-T/rs1800629-G haplotype in AD (P=0.012; OR, 1.60; 95% CI, 1.11-2.29), although to a lesser degree than rs1799724-T alone. Further, the rs1799724-T allele was found to be associated with lower levels of CSF Abeta42 (P=0.023), thus corroborating the genetic findings. Inheritance of the rs1799724-T allele appears to synergistically increase the risk of AD in APOEepsilon4 carriers and is associated with altered CSF Abeta42 levels. Further investigations are warranted to assess the significance of these novel findings.     

Relationship between apoE genotype and CSF beta-amyloid (1-42) and tau in patients with probable and definite Alzheimer's disease

We investigated the usefulness of cerebrospinal fluid (CSF) beta-amyloid42 (Abeta42), beta-amyloid40 (Abeta40) and tau analyses in the diagnosis of Alzheimer's disease (AD). The study included 41 definite AD cases, 80 patients with probable AD. 27 with other dementias and 39 neurological controls. Abeta42, Abeta340 and tau protein concentrations in CSF were measured of using ELISA assays. Abeta42 levels were decreased and tau increased in AD. Combination of Abeta42 and tau resulted a sensitivity of 50.4% for AD and specificities of 94.8% for controls and 85.2% for other dementias. Ninety-one percent of the patients with Abeta42 below the cutoff value (340 pg/ml) and tau above the cutoff value (380 pg/ml) had AD. AD patients carrying apoE epsilon4 allele had lower Abeta42 (P < 0.005) and higher tau (P < 0.05) levels than those without an E4 allele, and 18 (81.8%) of the 22 AD patients who had normal Abeta42 and tau levels were apoE e4 allele non-carriers. Low Abeta42 and high tau concentration in CSF strongly support the diagnosis of AD. Measurement of Abeta42 may help the early diagnosis of cases at risk for AD such as apoE E4 allele carriers.     

Association of CSF apolipoprotein E, Abeta42 and cognition in Alzheimer's disease.

A significant association between CSF Abeta42 and cognition in patients with Alzheimer's disease (AD) homozygous for the epsilon3 allele of the apolipoprotein E (apoE) has been described. In this study we extended our observations on apoE, as another plaque component, and investigated the association between CSF apoE concentrations and cognitive performance after stratification for the apoE genotype in 62 patients with AD, 19 other forms of dementia and 18 controls. CSF Abeta42 and apoE concentrations were significantly and positively associated with Mini Mental State Examination (MMSE) score in AD (Abeta42: r = 0.332; P = 0.026; apoE: r = 0.386; P = 0.006). For Abeta42 this association was exclusively present in epsilon3 homozygotes (r = 0.44; P = 0.014), whereas apoE was correlated with MMSE in epsilon4 hetero- or homozygotes subjects (epsilon4/epsilonX: r = 0.638; P = 0.004: epsilon4/epsilon4; r = 0.812; P = 0.05). No association was observed between CSF concentrations of Abeta42 and apoE. The significant relationship between MMSE and CSF Abeta42 in epsilon3 homozygotes and apoE in epsilon4 hetero- and homozygotes respectively may suggest that both proteins may be associated independently from each other with cognitive decline.     

Apolipoprotein E epsilon4 is associated with atrophy of the amygdala in Alzheimer's disease

Although the ApoE epsilon4 allele is well-established as the most important genetic risk factor for Alzheimer's disease (AD), the effects of this allele on regional brain atrophy in AD patients remain controversial. We performed MRI-based volumetric measurements of the hippocampus and amygdala (normalized to intracranial volume) in 32 epsilon4+ AD patients, 23 epsilon4- AD patients, and 42 cognitively normal elderly control subjects. Analysis of covariance revealed that amygdaloid volume was significantly smaller (19.2%) in ApoE epsilon4+ than epsilon4- AD patients, controlling for disease severity (F = 10.62; d.f. = 1,52; p = 0.002; ANCOVA). Alternatively, when ApoE epsilon4 dose was considered, this effect appeared to accrue from a difference between the 0epsilon4 and each of the other two AD groups, with no significant difference between the 1epsilon4 and 2epsilon4 AD groups. Hippocampal volumes and asymmetry indices for hippocampus and amygdala did not differ between epsilon4 carriers and noncarriers. These results suggest accelerated atrophy of the amygdala in AD in association with ApoE epsilon4 and provide further evidence for regionally specific effects of this allele.     

The effects of normal aging and ApoE genotype on the levels of CSF biomarkers for Alzheimer's disease

While cerebrospinal fluid (CSF) biomarkers are of use in the prediction and diagnosis of Alzheimer's disease our understanding of the background effects of age and the ApoE genotype is limited. Seventy-eight community-based normal volunteers (mean age 60+/-10 years, range 36-86) were examined to determine the relationships between CSF measures of total tau (T-tau), hyperphosphorylated tau (P-tau 231), amyloid beta (Abeta42/Abeta40 ratio), and isoprostane (IP) with age and ApoE genotype. The results showed that age by epsilon4 genotype interactions were found for P-tau231 (beta=1.82; p<0.05) and IP (beta=1.6; p<0.05). T-tau CSF concentration increased with age. The increasing CSF concentrations of P-tau and IP in epsilon4 carriers suggest that early tauopathy and oxidative stress may be related to the increased risk for AD. The data also suggest that T-tau changes are more age dependent than Abeta changes. The evidence that P-tau231 and IP are the earliest markers for the neuronal damage related to AD awaits longitudinal study.     

Is ApoE gene a risk factor for vascular dementia in Han Chinese?

We have compared the apolipoprotein E (ApoE) genotypes of Han Chinese with late-onset sporadic Alzheimer's disease (LOAD, n=191), and vascular dementia (VaD, n=124) to controls (n=218) with a similar age distribution. The frequency of ApoE epsilon4 allele in the LOAD group was significantly higher than that in the control group (30.1% versus 10.55%, p<10-7). The risk rate of LOAD was 3.5 times higher for carriers with at least one ApoE epsilon4 allele than for non-epsilon4 bearing controls. ApoE epsilon4 allele was also significantly associated with vascular dementia (OR=1.75, p=0.026). Our findings support previous reports of a positive association between ApoE epsilon4 and both Alzheimer's disease and vascular dementia in Han Chinese.     

The interaction between sleep-disordered breathing and apolipoprotein E genotype on cerebrospinal fluid biomarkers for Alzheimer's disease in cognitively normal elderly individuals

Previous studies have suggested a link between sleep disordered breathing (SDB) and dementia risk. In the present study, we analyzed the relationship between SDB severity, cerebrospinal fluid (CSF) Alzheimer's disease-biomarkers, and the ApoE alleles. A total of 95 cognitively normal elderly participants were analyzed for SDB severity, CSF measures of phosphorylated-tau (p-tau), total-tau (t-tau), and amyloid beta 42 (Aβ-42), as well as ApoE allele status. In ApoE3+ subjects, significant differences were found between sleep groups for p-tau (F[df2] = 4.3, p = 0.017), and t-tau (F[df2] = 3.3, p = 0.043). Additionally, among ApoE3+ subjects, the apnea and/or hypopnea with 4% O₂-desaturation index was positively correlated with p-tau (r = 0.30, p = 0.023), t-tau (r = 0.31, p = 0.021), and Aβ-42 (r = 0.31, p = 0.021). In ApoE2+ subjects, the apnea and/or hypopnea with 4% O₂-desaturation index was correlated with lower levels of CSF Aβ-42 (r = −0.71, p = 0.004), similarly to ApoE4+ subjects where there was also a trend toward lower CSF Aβ-42 levels. Our observations suggest that there is an association between SDB and CSF Alzheimer's disease-biomarkers in cognitively normal elderly individuals. Existing therapies for SDB such as continuous positive airway pressure could delay the onset to mild cognitive impairment or dementia in normal elderly individuals.     

Interest of CSF beta-amyloid1-42 and t-tau protein level determinations for the diagnosis of Alzheimer's disease

Early diagnosis of Alzheimer's disease remains a tactful poser. In order to clarify the importance of beta amyloid protein dosage (Abeta1-42) and protein tau (t-tau) in such pathology, we have rigorously studied three well recruited populations that match in age: healthy controls (n = 32), Alzheimer patients (n = 87) and non Alzheimer dementia (n = 31) patients. The combination of Abeta1-42 and t-tau at baseline yielded a sensitivity of 85.29 % for detection of Alzheimer's disease and the specificity was by 96.77 % to differentiate controls. So the combination of these tow markers helps in the diagnosis of Alzheimer because of the high specificity and sensibility of this method.     

Dihydropyridine-sensitive calcium currents in bipolar cells of salamander retina are inhibited by reductions in extracellular chloride

Apolipoprotein E (APOE) genotypes and cerebrospinal fluid (CSF) tau protein concentration were evaluated in patients suffering from semantic dementia, with the aim of determining whether these markers could help to differentiate this condition from Alzheimer's disease (AD) in early stages. By strictly following diagnostic criteria for semantic dementia, we found a clinically homogeneous group comprising eight patients from a total population of 621 subjects referred for dementia investigation. CSF tau protein concentrations were moderately increased with a small intraindividual variation 437+/-36 pg/ml (mean+/-SD) compared to healthy control individuals. APOE genotype distribution showed an over representation of the epsilon4 allele (69% epsilon3, 31% epsilon4 and no epsilon2), a pattern similar to that found in AD. These results indicate that semantic dementia is a rather uncommon but clinically distinct condition which shows a moderate increase of CSF tau protein levels and for which the epsilon4 allele is a risk factor.     

Apolipoprotein E as vascular risk factor in neurodegenerative dementia

Apolipoprotein E (ApoE) is the major lipid-carrier protein in the brain, and several studies provided evidence that ApoE epsilon4 allele can be considered a genetic risk factor for vascular diseases. Findings indicate that Alzheimer disease (AD) and vascular dementia (VaD) may have common risk factors and/or pathogenesis, but their interrelationships still need to be clearly defined. Since ApoE4 imparts risk for both hyperlipidemia and AD, it seemed worthwhile to investigate the possible role of ApoE in the pathogenesis of AD and VaD. To this task, we examined in healthy volunteers, and AD and VaD patients: i) the frequency of ApoE isoforms; and ii) the influence of ApoE genotype on serum lipid levels. Our findings suggest that epsilon4 allele is an important risk factor for the development not only of the Alzheimer type, but also of the vascular type of dementia. In contrast, epsilon2 allele could have a protective role in AD dementia. These results confirm the hypothesis that serum ApoE concentration is dependent on ApoE genotype, but do not support the view that it has to be considered a relevant biochemical marker for AD and VaD.     

The normal equilibrium between CSF and plasma amyloid beta levels is disrupted in Alzheimer's disease

Amyloid-beta (Abeta) with 40 (Abeta40) and 42 (Abeta42) amino acids, the main components of amyloid plaques in the Alzheimer's disease (AD) brain, can be measured in human cerebrospinal fluid (CSF) and plasma. Whereas CSF Abeta42 is decreased in AD, some studies have reported changed plasma Abeta levels in AD and in subjects with mild cognitive impairment (MCI). To this date it is unclear if and how CSF and plasma levels of Abeta correlate with each other in healthy individuals, albeit earlier studies on AD patients found no correlation between CSF and plasma Abeta. We have measured Abeta40 and Abeta42 in paired CSF and plasma samples from patients with AD (n=39), MCI (n=29) and healthy control subjects (n=18). We observed a clear correlation between CSF and plasma levels for both Abeta40 and Abeta42 in healthy individuals, whereas no such correlation could be seen for AD or MCI cases. Similarly to other studies we also found low levels of Abeta42 in AD CSF, whereas there were no significant differences in plasma Abeta levels between the diagnostic groups. Our findings suggest that the normal equilibrium between CSF and plasma Abeta may be disrupted with the initiation of amyloid deposition in the brain.     

Evaluation of plasma Abeta(40) and Abeta(42) as predictors of conversion to Alzheimer's disease in patients with mild cognitive impairment

Numerous studies have shown a marked decrease of beta-amyloid(42) (Abeta(42)) in the cerebrospinal fluid (CSF) of patients with incipient Alzheimer's disease (AD). However, studies on Abeta in plasma are contradictory, and show very marginal differences between patients and controls. Here, we analyzed plasma samples using a new multiplex immunoassay for simultaneous analysis of Abeta(1-40), Abeta(n-40), Abeta(1-42), and Abeta(n-42). The plasma samples were obtained at baseline from two independent cohorts of patients with mild cognitive impairment (MCI) and age-matched controls. In the first cohort, 41% of the 117 MCI cases converted to AD during a clinical follow-up period of 4-7 years. In the second cohort, 14% of the 110 MCI subjects developed AD during a clinical follow-up period of 2-4 years. None of the plasma Abeta isoforms differed between MCI patients that subsequently developed AD and healthy controls or stable MCI patients. The Cox proportional hazards model did not reveal any differences in the probability of progression from MCI to AD related to plasma Abeta levels. In contrast, low levels of Abeta(1-42) in CSF were strongly associated with increased risk of future AD. The absence of a change in plasma Abeta in incipient AD, despite the marked change in CSF, may be explained by the lack of a correlation between the levels of Abeta(1-42) in CSF and plasma. In conclusion, the results show that CSF biomarkers are better predictors of progression to AD than plasma Abeta isoforms.     

Intronic CYP46 polymorphism along with ApoE genotype in sporadic Alzheimer Disease: from risk factors to disease modulators

Increasing biological and clinical findings argue for a link between brain cholesterol turnover and Alzheimer Disease (AD), high cerebral levels of the former increasing Abeta load. Cerebral cholesterol elimination involves two mechanisms dependent on Apolipoprotein E (ApoE) and cholesterol 24-hydroxylase (CYP46). The aim of this study was to evaluate an intronic variation in CYP46 (intron 2, T --> C ) along with ApoE genotype as risk factors for AD and to establish the correlation between CYP46/ApoE polymorphism and disease progression. One-hundred and fifty-seven AD patients, who had been followed periodically through 1-year follow-up after enrollment, and 134 age- and gender-matched controls entered the study. The distribution of CYP46 genotypes was significantly different in AD compared to controls (P<0.004), being CYP*C allele higher in AD patients ( P<0.002). ApoE 4 genotype was more frequent in AD (41.4%) than in controls (15.9%, P<0.0001). The odds ratio (OR) for AD risk in CYP46*C carriers was 2.8, and in ApoE epsilon4 carriers was 4.05; the OR for having both CYP46*C and ApoE epsilon4 was 17.75, demonstrating the their synergic effect on AD risk. In AD patients, CYP46*C along with ApoE epsilon4 genotype were associated with a higher cognitive decline at 1-year follow-up (P<0.02). These findings provide direct evidence that CYP46 and ApoE polymorphisms synergically increase the risk for AD development, and influence on the rate of cognitive decline.     

C4b-binding protein in Alzheimer's disease: binding to Abeta1-42 and to dead cells

In the Alzheimer's disease (AD) brain, binding of Clq within the Cl complex, the initiating molecule of the classical complement pathway, to apoptotic cells, DNA and amyloid-beta (Abeta), the major constituent of senile plaques, can initiate complement activation. However, the extent of activation is determined by the balance between activation and inhibition. Fluid-phase complement inhibitor C4b-binding protein (C4BP) was immunohistochemically detected in Abeta plaques and on apoptotic cells in AD brain. In vitro, C4BP bound apoptotic and necrotic but not viable brain cells (astrocytes, neurons and oligodendrocytes) and limited complement activation on dead brain cells. C4BP also bound Abeta1-42 peptide directly, via the C4BP alpha-chain, and limited the extent of complement activation by Abeta. C4BP levels in cerebrospinal fluid (CSF) of dementia patients and controls were low compared to levels in plasma and correlated with CSF levels of other inflammation-related factors. In conclusion, C4BP binds to dead brain cells and Abeta peptide in vitro, is present in CSF and possibly protects against excessive complement activation in AD brains.     

载脂蛋白E在阿尔茨海默病中的表达及其意义

目的探讨载脂蛋白E（apoE）基因多态性和ε4等位基因与阿尔茨海默病（Alzheimer disease,AD）的关系,以及apoE在AD老年斑形成过程中的作用。方法从北京医院病理科1982—2003年尸检材料中选出27例AD,均按照美国多中心合作建立的阿尔茨海默病的病理诊断标准诊断,其中23例为肯定AD,4例为可疑AD。另选年龄相仿的对照组67例,为北京医院病理科同期非神经系统疾病死亡的尸检标本。分别应用免疫组织化学SP法检测β-淀粉蛋白（β-amyloid,AB）、Tau蛋白,以及SP法和ABC法免疫组织化学双标技术检测Aβ／apoE在AD脑组织中的表达;对23例肯定AD脑组织进行老年斑和神经原纤维缠结计数及形态学观察。应用聚合酶链反应-限制性片段长度多态性（PCR—RFLP）技术,对所有的AD及对照组标本进行apoE基因多态性分析。结果AB免疫组织化学染色显示AD脑组织内有4种不同类型的老年斑,即弥漫性非神经突斑、弥漫性神经突斑、有核心的神经突斑、有核心的非神经突斑。Aβ／apoE免疫组织化学双标染色显示有的老年斑A6和apoE均阳性,其在上述4种类型的老年斑中阳性表达率分别为4．28％、84．71％、8．50％、2．51％,弥漫性神经突斑Aβ／apoE免疫组织化学双标染色均阳性的表达率明显高于其他类型老年斑,P〈0．01。AD组apoEε4等位基因的频率明显高于对照组,P〈0．01。23例肯定的AD中,具有apoEε4等位基因的AD脑组织内的老年斑和神经原纤维缠结的数量均明显多于无apoEε4等位基因的AD脑组织,P〈0．01。结论apoE基因多态性与AD发生有关;apoEaε4等位基因是AD发病的重要危险因素,与AD脑组织病变的形成和进展有密切关系;apoE蛋白可能在AD弥漫性非神经突斑向弥漫性神经突斑进展过程中发挥了重要作用。     

The apolipoprotein E ε4 allele plays pathological roles in AD through high protein expression and interaction with butyrylcholinesterase

The apolipoprotein E (ApoE) ε4 allele has consistently been established as an Alzheimer's disease (AD) risk factor, but its pathological contribution to AD is obscure. Certain butyrylcholinesterase (BuChE) polymorphisms together with the ApoE ε4 allele synergistically increase the risk of AD. In addition, AD risk factors, i.e. advanced age, female gender and ApoE ε4 are associated with different levels of CSF BuChE in AD patients, and BuChE protein attenuates Aβ fibrillization in vitro. Here we investigated the roles of ApoE and BuChE gene products as modulators of pathological features of AD in vivo. We found that AD risk factors were associated with different levels of ApoE protein in the CSF of AD patients (n = 115). Women and ApoE ε4 carriers had the highest levels of ApoE protein (up by 50-120%, p < 0.01-0.0001), which were increased with age (r = 0.30, p < 0.0006). The CSF surrogate markers of pathological features of AD, i.e. high tau and P-tau, low Aβ₄₂ and high tau/Aβ₄₂ ratio, were associated with high levels of ApoE protein. Intriguingly, high ApoE protein levels were not only associated with low amounts of BuChE, but they also altered the aging and activity of this enzyme in concentration- and isoform-dependent manners, particularly in the presence of Aβ peptides. Both ApoE and BuChE levels were also differentially related to levels of the proinflammatory cytokine IL-1β. In conclusion, ApoE ε4 might impart its pathological role through high protein expression and interaction with BuChE, which in turn might modulate central cholinergic activity and Aβ load in the brain.     

Reduced hippocampal insulin-degrading enzyme in late-onset Alzheimer's disease is associated with the apolipoprotein E-epsilon4 allele

Abeta is the major component of amyloid plaques characterizing Alzheimer's disease (AD). Abeta accumulation can be affected by numerous factors including increased rates of production and/or impaired clearance. Insulin-degrading enzyme (IDE) has been implicated as a candidate enzyme responsible for the degradation and clearance of Abeta in the brain. We have previously shown that AD patients exhibit abnormalities in insulin metabolism that are associated with apoliprotein E (APOE) status. The possible association of IDE with AD, as well as the link between APOE status and insulin metabolism, led us to examine the expression of IDE in AD. We report that hippocampal IDE protein is reduced by approximately 50% in epsilon4+ AD patients compared to epsilon4- patients and controls. The allele-specific decrease of IDE in epsilon4+ AD patients is not associated with neuronal loss since neuron-specific enolase levels were comparable between the AD groups, regardless of APOE status. Hippocampal IDE mRNA levels were also reduced in AD patients with the epsilon4 allele compared to AD and normal subjects without the epsilon4 allele. These findings show that reduced IDE expression is associated with a significant risk factor for AD and suggest that IDE may interact with APOE status to affect Abeta metabolism.     

ApoE epsilon3-haplotype modulates Alzheimer beta-amyloid deposition in the brain

ApoE epsilon4 allele increases the risk of late-onset Alzheimer disease (AD) as well as the amount of beta-amyloid deposition in the brain. Because half of AD patients do not have ApoE epsilon4, it is important to search for other determinants of ApoE that modify AD risk. We tested whether the haplotype background of the most common ApoE allele, epsilon3, influences brain amyloid deposition or the risk of neuropathologically verified AD in a population-based sample of elderly Finns. To exclude the effects of ApoE protein polymorphism we focused these analyses on subjects homozygous for epsilon3. Haplotypes were defined using polymorphisms at positions - 491 and -219 of the ApoE promoter and at position +113 of intron-1. We found that epsilon3-haplotypes containing the promoter allele -219T were associated with reduced amyloid deposition and reduced risk of neuropathologically verified AD as compared to epsilon3-haplotypes containing -219G. The functional polymorphism(s) responsible for the haplotypic difference remains to be identified. These results indicate that there is significant allelic variation in the ApoE gene region, which modulates brain amyloid deposition and AD risk, independent of the ApoE protein polymorphism.