Apolipoprotein E genotype influences spatial distribution of cerebral microbleeds

In cerebral amyloid angiopathy patients, microbleeds often cluster, mostly occipital, and are associated with apolipoprotein E (APOE) genotype. Microbleeds also frequently occur in the asymptomatic, general population. In this population, we investigated spatial distribution of microbleeds and whether this is influenced by APOE genotype. In 292 persons with microbleeds, we labeled microbleeds on baseline and follow-up magnetic resonance images. We calculated distance between incident and prevalent microbleeds within and between persons and performed lobar segmentation on the magnetic resonance images. Subsequently, we investigated proximity and lobar distribution in strata of APOE genotype. Microbleeds occurred closer within persons than between persons (−42.2 mm, 95% confidence interval, −44.6 to −39.9; p < 0.001). Microbleeds within APOE ε2 and ε4 carriers occurred closer than those in persons with ε3ε3 genotype (−11.9 mm, 95% confidence interval, −24.4 to 0.6; p = 0.06). Persons with ε2 and ε4 alleles had a larger proportion of microbleeds in the occipital lobe than persons with ε3ε3 genotype. Similar to cerebral amyloid angiopathy patients, microbleeds in the general population cluster and the distribution is affected by APOE genotype.     

Alzheimer's disease patients not carrying the apolipoprotein E ε4 allele show more severe slowing of oscillatory brain activity

The objective of this study was to quantitatively assess the relationship between apolipoprotein (APOE) genotype and electroencephalographic oscillatory brain dynamics in Alzheimer's disease (AD) patients and control subjects and its regional distribution. We obtained resting-state electroencephalographs of 320 AD patients and 246 control subjects, categorized into APOE ε4 carriers and noncarriers. Peak frequency and relative power in 4 different frequency bands were calculated. We tested the associations between APOE genotype and relative power in 4 brain regions. Peak frequency was comparable in APOE ε4 carrying and noncarrying control subjects, but lower in APOE ε4 noncarrying AD patients. In control subjects, APOE ε4 carriers had a different regional distribution of alpha power than noncarriers. We found no APOE effect in beta, delta, and theta bands. In AD, APOE ε4 noncarriers had lower alpha and higher delta power than carriers. This difference was most pronounced in the parieto-occipital region. In the theta band, APOE ε4 noncarriers had a different regional distribution of power compared with carriers. In conclusion, the most pronounced effect of genotype was seen in AD patients, and APOE ε4 noncarriers showed slower activity, especially in parieto-occipital regions.     

BDNF Val66Met polymorphism is associated with Stage III-IV endometriosis and poor in vitro fertilization outcome

BACKGROUND The recently identified human brain-derived neurotrophic factor (BDNF) Val66Met polymorphism was found to be associated with altered susceptibility to some neuropsychiatric disorders. Interestingly, BDNF together with its receptors TrkB and p75 are extensively expressed in female reproduction system. The aim of this study is to investigate whether the BDNF Val66Met polymorphism plays a role in endometriosis, endometriosis-related infertility and the outcomes of IVF and embryo transfer (IVF-ET). METHODS A case-control study included 425 endometriosis patients and 244 control Chinese Han women. The genotyping of the BDNF Val66Met polymorphism was performed by the fluorescence resonance energy transfer method. The plasma and follicular fluid concentrations of BDNF on the day of oocyte retrieval were measured by ELISA. The general clinical data from the endometriosis-related and tubal obstructed infertile patients treated with IVF-ET were analyzed. RESULTS There was no association between the BDNF Val66Met polymorphism and overall endometriosis (P> 0.05), whereas higher genotype and allele frequencies of the BDNF(Met) polymorphism were found in the Stage III-IV endometriosis (both P< 0.01) and endometriosis-related infertile patients (both P< 0.05). Moreover, during IVF and embryo transfer (IVF-ET) treatment, fewer mature oocytes (P< 0.05) and lower fertilization rate (P< 0.01) were found in BDNF(Met/Met) carriers compared with those in BDNF(Val/Val) carriers with infertility. Follicular-fluid BDNF concentration in BDNF(Met/Met) carriers was lower compared with that in BDNF(Val/Val) individuals (P< 0.01). CONCLUSIONS Our results suggest that the BDNF(Met) single-nucleotide polymorphism might contribute to the increased susceptibility to the Stage III-IV endometriosis and endometriosis-related infertility. Moreover, infertile patients with the BDNF(Met/Met) genotype had a poorer IVF outcome compared with the BDNF(Val/Val) genotype individuals, which might in part be due to the decreased BDNF levels in follicular fluids after controlled ovarian hyperstimulation.     

Promoter -817C>T variant of B lymphocyte stimulator gene (BLyS) and susceptibility to endometriosis-related infertility and idiopathic infertility in Brazilian population

Many theories have been proposed to explain the development of endometriosis, and recently, autoimmune aetiology has been suggested. Besides, it is well known that endometriosis, especially the advanced disease, may impair fertility. B lymphocyte stimulator (BLyS) is a cytokine produced by macrophages and is necessary for normal B cell development. One of the most studied polymorphisms is the -817C/T in the promoter region of the gene. We aimed to assess the association between endometriosis-related infertility and idiopathic infertility and the BLyS -817C/T polymorphism in a Brazilian population. We performed a case-control study comprising 165 infertile women with endometriosis, 83 with idiopathic infertility and 145 fertile and assessed the association with BLys -817C/T polymorphism. BLyS -817C/T polymorphism was detected using TaqMan PCR. The results were analysed statistically, and a P-value < 0.05 was considered significant. The results disclosed similar genotype and allelic frequencies between endometriosis-related infertility (P = 0.225) and control group, regardless of the disease stage (P = 0.213 and P = 0.462, respectively). However, a statistically significant difference was observed regarding idiopathic infertile group (P = 0.048) compared with controls. Considering the dominant and recessive inheritance models, no significant differences in both endometriosis and idiopathic infertility group were found. The genotype frequencies were in Hardy-Weinberg equilibrium in all studied groups. The results point to a possible association between BLyS -817C/T polymorphism and idiopathic infertility in Brazilian population.     

Gene dose of apolipoprotein E and age-related hearing loss

Next to outer hair cell dysfunction, age-related hearing loss may be explained by apolipoprotein E (APOE) genotype. In the Leiden 85-plus Study, a population-based study, the participants were 85 years old. We measured hearing loss by pure-tone audiometry in 435 participants in relation to APOE. Results demonstrated that those with the APOE-ε4/ε4 genotype had the highest levels of hearing loss (n = 6; 56.1 dB), those with the APOE-ε3/ε4 or ε2/ε4 genotype (n = 89) had intermediate levels of hearing loss (51.0 dB), and those without the APOE-ε4 allele (n = 340) had the lowest levels of hearing loss (48.9 dB), p for trend = 0.02. Eighty percent of participants had hearing loss of 35 dB and more, that is, hearing impairment. The APOE-ε4 allele was associated with a 2.0-fold increased risk of hearing impairment (confidence interval [CI 95%], 1.0-4.0), compared with those without the APOE-ε4 allele. The risk for hearing impairment in subjects with the APOE-ε4 allele remained similar after adjustment for cardiovascular disease, stroke, and cognitive impairment. Our results suggest that the APOE-ε4 allele contributes to age-related hearing loss.     

The effects of APOE-ε4 on the BOLD response

In the last decade, functional magnetic resonance imaging (fMRI) has emerged as a tool to study changes in brain function associated with a genetic risk for Alzheimer's disease (AD), with a particular focus on the effects of the APOE-ε4 allele. This review compiles the existing literature concerning the effects of APOE genotype on the blood oxygen level dependent (BOLD) response, measured during task-based functional magnetic resonance imaging. While most studies report a significant difference in brain activity between carriers and noncarriers of the ε4 allele, there are inconsistencies in the direction and location of change. These inconsistencies were addressed by examining the effect of task, family history of Alzheimer's disease, and age on the relationship between APOE genotype and the BOLD response, but no clear pattern emerged. The review discusses the interpretation of BOLD differences between ε4 carriers and noncarriers, provides suggestions for future studies, and highlights important limitations of this type of research.     

Apolipoprotein E genotype ε4/ε2 in the STANISLAS Cohort Study - Dominance of the ε2 allele ?

Apolipoprotein (apo) E has been discussed as a marker for cardiovascular risk, but information about lipid traits in healthy individuals having one of the rare apoE genotypes (ε4/ε2, ε2/ε2 or ε4/ε4) is scarce. Our work was designed to answer the following questions: 1. Are the allelic effects of ε2 and ε4 on lipid traits additive or dominant? 2. If there is additivity, do the allelic effects of ε2 and ε4 have the same magnitude? 3. Are the allelic effects neutralised in ε4/ε2 individuals who are under the influence of both rare alleles? Allelic effects on apoB and apoE serum levels were codominant. Allelic models are thus not adequate to study the influence of apoE polymorphism on these traits. Allelic effects were additive for total cholesterol, LDL-C, HDL-C and apoAI, with ε2 having a greater impact than ε4. Serum levels differed significantly between ε4/ε2 and ε3/ε3 individuals only for apoE (p < 0ε001) and for apoB (p < 0ε05).     

SLCO1B1/ApoE基因多态性与瑞舒伐他汀疗效及安全性的相关性研究

目的 探讨SLCO1B1与ApoE基因多态性对瑞舒伐他汀的降脂疗效和安全性的相关性.方法 采用纳米磁珠法提取全血基因组DNA,PCR-焦磷酸测序法检测SLCO1B1与ApoE基因多态性.152名受试者口服瑞舒伐他汀10 mg/d,通过检测用药前以及用药8周后的低密度脂蛋白胆固醇(LDL-C)水平,评价降脂疗效;通过随访用药期间肌痛的发生,评价肌病不良反应的发生频率.结果 152名受试者SLCO1B1 521T＞C基因型分布为TT 73.7％,TC 23.7％,CC 2.6％;ApoE基因型分布为ε3/ε3 65.8％,ε3/ε213.2％,ε4/ε3 21.0％,未见ε4/ε4、ε2/ε2、ε4/ε2基因型.瑞舒伐他汀治疗8周后,APOE ε3/ε3,ε3/ε3与ε4/ε3基因组比较,患者血浆中的LDL-C下降水平有统计学意义(P＜0.05);SLCO1B1 521T＞C 3种基因型发生肌痛的频率明显不同(P＜0.05).结论 SLCO1B1/ApoE基因多态性与瑞舒伐他汀疗效及安全性具有相关性,联合检测SLCO1B1与ApoE基因型有助于预测疗效和不良反应,实现瑞舒伐他汀的个体化用药.     

Evolution of human apolipoprotein E (APOE) isoforms: Gene structure,protein function and interaction with dietary factors

Apolipoprotein E (APOE) is a member of the vertebrate protein family of exchangeable apolipoproteins that is characterized by amphipathic α-helices encoded by multiple nucleotide tandem repeats. Its equivalent in flying insects − apolipophorin-III − shares structural and functional commonalities with APOE, suggesting the possibility of an evolutionary relationship between the proteins. In contrast to all other known species, human APOE is functionally polymorphic and possesses three major allelic variants (ε4, ε3 and ε2). The present review examines the current knowledge on APOE gene structure, phylogeny and APOE protein topology as well as its human isoforms. The ε4 allele is associated with an increased age-related disease risk but is also the ancestral form. Despite increased mortality in the elderly, ε4 has not become extinct and is the second-most common allele worldwide after ε3. APOE ε4, moreover, shows a non-random geographical distribution, and similarly, the ε2 allele is not homogenously distributed among ethnic populations. This likely suggests the existence of selective forces that are driving the evolution of human APOE isoforms, which may include differential interactions with dietary factors. To that effect, micronutrients such as vitamin D and carotenoids or dietary macronutrient composition are elucidated with respect to APOE evolution.     

APOLIPOPROTEIN E POLYMORPHISM AND STROKE IN A POPULATION FROM EASTERN TURKEY

Human apolipoprotein E (apo E) alleles are polymorphic with significantly different frequencies among different ethnic groups and have been associated with increased risk of coronary heart disease, and postulated as a major genetic susceptibility locus for Alzheimer's disease. Studies undertaken in different populations have shown different association patterns between apo E genotype and stroke. The aim of this study was to determine the risk of apo E genotype in stroke patients living in the eastern part of Turkey. The apo E genotypes and allele frequencies of 229 individuals from the same geographic area were determined by polymerase chain reaction and restriction fragment length polymorphism, of which 103 were patients with a documented history of stroke without other apparent dementia and 126 age-matched healthy subjects as a control group. A reduced E3/4 genotype frequency was found in subjects with stroke and the E2/3 genotype frequency was elevated in patients with previous stroke. There was no association between apo E ε4 allele and stroke. The APOE alleles had divergent effects in this population. Association between APOE (the gene) alleles and stroke in this population may be altered due to interaction with other genetic effects. The effects of APOE alleles and genotypes require further study in different populations.     

ESR1 rs9340799 Is Associated with Endometriosis-Related Infertility and In Vitro Fertilization Failure

Estrogen receptor alpha has a central role in human fertility by regulating estrogen action in all human reproductive tissues. Leukemia inhibitory factor (LIF) expression, a cytokine critical for blastocyst implantation, is mediated by estrogen signaling, so we hypothesized that ESR1 gene polymorphisms might be candidate risk markers for endometriosis-related infertility and in vitro fertilization (IVF) failure. We included 98 infertile women with endometriosis, 115 infertile women with at least one IVF failure and also 134 fertile women as controls. TaqMan SNP assays were used for genotyping LIF (rs929271), MDM2 (rs2279744), MDM4 (rs1563828), USP7 (rs1529916), and ESR1 (rs9340799 and rs2234693) polymorphisms. The SNP ESR1 rs9340799 was associated with endometriosis-related infertility (P < 0.001) and also with IVF failure (P = 0.018). After controlling for age, infertile women with ESR1 rs9340799 GG genotype presented 4-fold increased risk of endometriosis (OR 4.67, 95% CI 1.84–11.83, P = 0.001) and 3-fold increased risk of IVF failure (OR 3.33, 95% CI 1.38–8.03, P = 0.007). Our results demonstrate an association between ESR1 rs9340799 polymorphism and infertile women with endometriosis and also with women who were submitted to IVF procedures and had no blastocyst implantation.     

Analysis of vitamin D receptor gene polymorphisms in women with and without endometriosis

An aberrant immunologic mechanism has been suggested to be involved in the pathogenesis of endometriosis. Genetic alterations in the vitamin D receptor gene (VDR) may lead to important defects in gene activation that principally affect immune function. We have hypothesized a possible relationship between endometriosis and/or infertility and the VDR polymorphisms (ApaI, TaqI, FokI, and BmsI). The study was a case-control study including 132 women with endometriosis-related infertility, 62 women with idiopathic infertility, and 133 controls. VDR polymorphisms were studied by restriction fragment length polymorphism. We found relatively similar VDR polymorphism genotype frequencies in cases and controls. When patients with minimal/mild and moderate/severe endometriosis were studied separately, no difference was found. When we compared infertile groups with and without endometriosis there was no statistically significant difference. The data suggest that VDR polymorphisms did not play an important role in the pathogenesis of endometriosis and/or infertility in the Brazilian women studied.     

How can elderly apolipoprotein E ε4 carriers remain free from dementia?

Apolipoprotein E (APOE) ε4 is a major risk factor for Alzheimer's disease (AD) and dementia, but not all ε4 carriers develop dementia. We sought to identify factors that may play a role in modifying the risk of dementia due to ε4. A cognitively intact cohort (n = 932, age ≥ 75) was followed for 9 years to detect incident dementia cases. At baseline, information on education, leisure activities, and vascular risk factors was collected, and APOE was genotyped. During the follow-up, 324 subjects developed dementia, including 247 AD cases. The hazard ratio (HR, 95% confidence interval [95% CI]) of dementia related to the ε4 was 1.39 (1.11–1.76), while the risk was reduced when ε4 carriers had high education, no vascular risk factors, or high score of leisure activities. Among ε4 carriers, the multiadjusted HRs of dementia that were associated with high education, high level of leisure activities, and absence of vascular risk factors were 0.59 (0.40–0.87), 0.49 (0.29–0.85), and 0.61 (0.41–0.90), respectively. The ε4 carriers with these factors had about 1.2 years delayed time to dementia onset compared with those without these factors. High education, active leisure activities, or maintaining vascular health seems to reduce the risk of dementia related to APOE ε4. The ε4 carriers with these characteristics appear to have similar dementia-free survival time to non-ε4 carriers.     

Progression from MCI to AD: Predictive value of CSF Aβ42 is modified by APOE genotype

Objective

To study CSF biomarkers amyloid-beta 1-42 (Aβ42) and total tau (tau) in relation to APOE genotype in their ability to predict progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD).

Methods

In 100 MCI patients CSF Aβ42, tau and APOE genotype were determined. At follow-up of 18 (13-24) months 58 patients remained non-progressive and 42 progressed to AD.

Results

Cox proportional hazards models showed an interaction between Aβ42 and APOE genotype (p < 0.05). Stratification for APOE revealed HR (95% CI) for abnormal Aβ42 of 8.2 (2.1-31.9) for ε4 non-carriers, 3.9 (0.8-18.5) for heterozygotes and 0.3 (0.0-1.7) for homozygotes. Inversely, stratification for Aβ42 revealed that in patients with normal levels of Aβ42, ε4 homozygotes had a strongly increased risk of progression to AD with HR (95% CI) 20.8 (2.4-182.8). Tau and APOE independently predicted progression to AD.

Conclusions

Aβ42 was a stronger predictor of progression to AD in APOE ε4 non-carriers than in carriers. Furthermore, the risk of progression for ε4 homozygotes was very high, also in patients with normal levels of Aβ42.     

The effects of APOE on brain activity do not simply reflect the risk of Alzheimer's disease

Possession of the APOE-ε4 allele is the best established genetic risk factor for sporadic Alzheimer's disease (AD), while the ε2 allele may confer protection against the disease. Previous functional magnetic resonance imaging (fMRI) studies have shown an effect of APOE genotype on brain function, typically by comparing only ε4 carriers with noncarriers. Here we included a wide range of genotype groups to determine how closely the effects of APOE on brain function are related to differences in relative risk for AD. We used functional magnetic resonance imaging (fMRI) to compare the pattern of activation during an episodic encoding task and during a counting Stroop task in 76 adults, aged 32 to 55, with different APOE genotypes (23 ε2/ε3, 20 ε3/ε3, 26 ε3/ε4, and 7 ε4/ε4). Strikingly, participants with an increased risk (ε4 carriers) and with a decreased risk (ε2 carriers) for AD both showed increased activation, relative to ε3 homozygotes, during both tasks. The increased activation was due to decreased deactivation or paradoxical activation of nontask-related regions of the brain, which suggests an intrinsic effect of APOE on the differentiation of functional cortical networks. These results question the often assumed link between APOE, the blood oxygenation level dependent (BOLD) response, and AD risk.     

Medial temporal lobe dysfunction during encoding and retrieval of episodic memory in non-demented APOE ε4 carriers

Presence of the apolipoprotein E (APOE) ε4 allele is linked to an increased risk to develop Alzheimer's dementia (AD). However, there are controversial data concerning the impact of the APOE genotype on cognitive functioning and brain activity in healthy subjects. We used event-related functional magnetic resonance imaging (fMRI) to investigate the effects of APOE genotype on spatial contextual memory encoding and retrieval success in healthy older adults. Eighteen subjects (eight APOE4 heterozygotes (ε4+) and 10 non-carriers (ε4−), mean age 60.0±5.0 years) were included in the present analysis. Behaviorally, ε4+ subjects performed significantly worse than ε4− subjects in item memory and spatial context retrieval. fMRI data revealed that ε4+ subjects, compared to ε4-subjects, predominantly showed an increase of neural activity specific to encoding of items and their spatial context in prefrontal, temporal and parietal regions. In contrast, ε4+ subjects showed activity decreases in the right amygdala during successful item recognition and in the prefrontal cortex bilaterally during spatial context retrieval when compared to ε4− subjects. While the activity increases during encoding may reflect compensatory activity in the attempt to maintain normal performance, the decreases during retrieval indicate incipient neural decline in ε4+ subjects. These data highlight that preclinical ApoE-related changes in neural activity are not unidirectional but dissociate depending on the memory phase, i.e., encoding or retrieval.     

Education halves the risk of dementia due to apolipoprotein ε4 allele: a collaborative study from the Swedish Brain Power initiative

A number of studies have explored the relationships of apolipoprotein E (APOE) genotype and education with dementia over the last decade. However, observations concerning the possible modifying effect of education on the APOE-dementia association are limited. The objective of this study was to test the hypothesis that education may decrease the risk of APOE ε4 on dementia. Pooled data from 3 major population-based studies in Northern Europe were used in this study, with a total of 3436 participants aged 65 and older derived from the Kungsholmen project and the Gothenburg Birth Cohort studies in Sweden, and the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) project in Finland. The main outcome measure was dementia, which was diagnosed in 219 persons according to standard criteria. APOE ε4 was associated with increased risk of dementia independent of the effect of education (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.9-3.4 for 1 ε4 carrier and OR, 3.7; 95% CI, 1.8-7.2 for 2 ε4 carriers). High education (8 years and more) was related to a lower dementia risk (OR, 0.5; 95% CI, 0.3-0.6). An interaction between education and APOE ε4 was observed. Compared with those with less education and no ε4, the odds of dementia among persons with low education who carried any ε4 allele was 2.7 (95% CI, 1.9-3.9), and 1.2 (0.7-1.8) if they had higher education. This study suggests that genetic (APOE ε4) and environmental (education) factors are not only independently but also interactively related to dementia risk and that high education may buffer the negative effect of APOE ε4 on dementia occurrence.     

ApoE gene polymorphism and its relationship with coronary artery disease in ethnic Kashmiri population

Apolipoprotein E is a fundamental component of various lipoproteins and plays substantial role in cholesterol/lipid transport among cells of various tissues. The ApoE gene is polymorphic with three alleles ε2, ε3, and ε4, coding for isoforms E2, E3, and E4 having different binding inclination for corresponding receptors. This work aimed to investigate the association between ApoE gene polymorphism and coronary artery disease (CAD) in Kashmiri population. APOE genotyping was done by polymerase chain reaction-restriction fragment length polymorphism. Our study indicated ApoE ε3/ε3 to be the most common genotype in both CAD and control group. The frequency of ε2, ε3, and ε4 alleles of ApoE gene in cases was observed to be 0.06, 0.72, and 0.20, while in control subjects it was 0.075, 0.82, and 0.11, respectively. A significant difference was found between cases and controls with respect to TC, LDL, and HDL levels. Our data showed that frequency of ε4/ε4, ε4/ε3 genotype and ε4 allele was significantly higher in cases than in controls (p = 0.02, p = 0.004, p < 0.001 respectively). Moreover, the CAD patients carrying ε4 allele had significantly higher TC and LDL levels (p value <0.01). Thus our data showed a significant association of ApoE ε4 allele with the risk of CAD. The data revealed that ApoE ε4 allele is associated with increased risk of CAD and increased levels LDL and TC in Kashmiri population.     

Brain tissue volumes by APOE genotype and leisure activity-the AGES-Reykjavik Study

This study investigates the association of the APOE ε4 allele and leisure activity with brain tissue volumes, including white matter hyperintensities (WMH), in a population-based cohort of 4303 nondemented individuals, aged 66-96 years. APOE ε4 carriers were shown to have greater WMH and cerebrospinal fluid (CSF) volumes than noncarriers but smaller gray matter (GM) volumes. There was no significant difference in white matter (WM) and total brain parenchymal (TBP) volumes between APOE ε4 carriers and noncarriers. Tests for linear trend showed that individuals with lower leisure activity levels had greater WMH and CSF volumes, smaller TBP, WM and GM volumes than those with the highest levels of participation. The significant positive trend of the leisure activity with the brain tissue volumes was observed in the APOE ε4 carriers as well as in noncarriers after adjustment for demographic and health factors. These cross-sectional data suggest leisure activity is associated with tissue volumes in the brain irrespective of the APOE ε4 risk allele status.     

Genetic polymorphism in the persyn (gamma-synuclein) gene and the risk of Alzheimer's disease

Alzheimer's disease (AD) is a complex disease with the possible involvement of several genes. Genetic studies on sporadic late-onset AD have determined APOE*4 to be the major risk factor. Members of the synuclein gene family are potential candidates for the risk of AD. The persyn gene (gamma-synuclein) has recently been characterized and a common polymorphism (Glu110Val) has been identified. In this study we investigated the association of this polymorphism with sporadic late-onset AD patients. We screened DNA samples of 313 late-onset cases and 352 controls. No significant association was observed between the missense mutation and AD. When the data were stratified by APOE*4 carriers and non-APOE*4 carriers, no difference was seen for the Glu110Val polymorphism. There was also no difference in genotype or allele frequency when stratified by the ACT*A allele. Although our data show no effect of this persyn polymorphism in AD, characterization of additional polymorphisms in this gene may provide more conclusive answers.