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1.  TREM2 and Neurodegenerative Disease 
The New England journal of medicine  2013;369(16):1564-1565.
doi:10.1056/NEJMc1306509#SA1
PMCID: PMC3980568  PMID: 24131184
2.  Apolipoprotein E and Familial Longevity 
Neurobiology of aging  2012;34(4):1287-1291.
Background
Exceptional longevity is associated with substantial heritability. The ε4 allele in Apolipoprotein E and the linked G allele in rs2075650 of TOMM40 have been associated with increased mortality and the ε2 allele with decreased mortality, although inconsistently.
Methods
Offspring from long lived families and spouse controls were recruited at three sites in the US and in Denmark. We used Generalized Estimating Equations to compare the likelihood of carrying risk alleles in offspring (n=2,307) and spouse controls (n=764), adjusting for age, sex, level of education and family membership.
Results
The likelihood of carrying an APOE ε4 allele or a G allele in rs2075650 was lower (OR=0.75, p =.005 and OR=0.70, p = .002) and the likelihood of carrying an APOE ε2 allele was higher (OR= 1.5, p = .007) among family members in the offspring generation than among their spouse controls.
Conclusions
Our findings support the hypothesis that both reduction in the frequency of the ε4 allele and increase in the frequency of the ε2 allele contribute to longevity.
doi:10.1016/j.neurobiolaging.2012.08.019
PMCID: PMC3545094  PMID: 23040522
Exceptional longevity; familial longevity; offspring; APOE; TOMM40
3.  C9ORF72 repeat expansions not detected in a group of patients with schizophrenia 
Neurobiology of aging  2012;34(4):1309.e9-1309.10.
A hexanucleotide repeat expansion in C9ORF72 was recently found to cause some cases of FTLD, FTD-ALS, and ALS. FTLD patients with the C9ORF72 repeat expansion are more likely than those without to present with psychosis. In this study, we screened DNA samples from 192 unrelated subjects with schizophrenia for the C9ORF72 repeat expansion. None of the subjects with schizophrenia had the pathogenic expansion. C9ORF72 repeat expansions either do not cause schizophrenia, or do so rarely (less than 1% of cases).
doi:10.1016/j.neurobiolaging.2012.08.011
PMCID: PMC3584690  PMID: 23036583
FTLD; Schizophrenia; C9ORF72 repeat expansion; psychosis
4.  Initial Assessment of the Pathogenic Mechanisms of the recently identified Alzheimer Risk Loci 
Annals of human genetics  2013;77(2):85-105.
SUMMARY
Recent genome wide association studies have identified CLU, CR1, ABCA7 BIN1, PICALM and MS4A6A/MS4A6E in addition to the long established APOE, as loci for Alzheimer’s disease. We have systematically examined each of these loci to assess whether common coding variability contributes to the risk of disease. We have also assessed the regional expression of all the genes in the brain and whether there is evidence of an eQTL explaining the risk. In agreement with other studies we find that coding variability may explain the ABCA7 association, but common coding variability does not explain any of the other loci. We were not able to show that any of the loci had eQTLs within the power of this study. Furthermore the regional expression of each of the loci did not match the pattern of brain regional distribution in Alzheimer pathology.
Although these results are mainly negative, they allow us to start defining more realistic alternative approaches to determine the role of all the genetic loci involved in Alzheimer’s disease.
doi:10.1111/ahg.12000
PMCID: PMC3578142  PMID: 23360175
Alzheimer’s disease; genetic risk; GWAS
5.  White matter hyperintensity volume and impaired mobility among older adults 
Journal of neurology  2012;260(3):884-890.
Gait speed is associated with multiple adverse outcomes of aging. White matter hyperintensities (WMH) on magnetic resonance imaging (MRI) have been associated with gait speed, though few studies have examined changes in gait speed over time in population-based studies comprising participants from diverse cultural backgrounds. The purpose of this study was to examine the association between a decline in gait speed and total and regional WMH volumes in a community-based study of aging. Participants (n=701) in a community-based study of older adults underwent gait speed measurement via a 4-meter walk test at the time of initial enrollment and MRI at a second time interval (mean 4.7[SD=0.5] years apart). Logistic regression was used to examine the association between large WMH volume and regional WMH volume with gait speed < 0.5 m/s (abnormal speed), and a transition to abnormal gait speed. Analyses were adjusted for demographic and clinical factors. Large WMH volume was associated with a transition to abnormal gait speed between the two visits, but not after adjustment for modifiable vascular disease risk factors. In adjusted models increased frontal lobe WMH volume was not associated with a transition to abnormal gait speed.
WMH are associated with slowing of gait over time. Prevention of WMH presents a potential strategy for the prevention of gait speed decline.
doi:10.1007/s00415-012-6731-z
PMCID: PMC3594567  PMID: 23128969
6.  Late Life Depression, Mild Cognitive Impairment and Dementia 
JAMA neurology  2013;70(3):374-382.
Objective
To evaluate the association of late life depression with mild cognitive impairment (MCI) and dementia and in a multi-ethnic community cohort.
Design
Cohort study
Setting
Northern Manhattan, New York city.
Participants
2160 community-dwelling Medicare recipients aged 65 years and older.
Methods
Depression was assessed using the 10-item version of the Center for Epidemiological Studies-Depression scale (CES-D) and defined by a CES-D score ≥ 4. We used logistic regression for cross-sectional association analyses and proportional hazards regression for longitudinal analyses.
Main outcome measures
MCI, dementia, and progression from MCI to dementia. We also used subcategories of MCI (amnestic, non amnestic), and dementia (probable AD, vascular dementia including possible AD with stroke).
Results
Baseline depression was associated with prevalent MCI (OR = 1.4; 95% CI: 1.11–1.9) and dementia (OR = 2.2; 95% CI :1.6–3.1). Baseline depression was associated with an increased risk of incident dementia (HR = 1.7; 95 % CI: 1.2–2.3), but not with incident MCI. Persons with MCI at baseline with co-existing depression had a higher risk of progression to dementia (HR = 2.3; 95% CI: 1.4–3.8), especially vascular dementia (HR = 4.3; 95% CI: 1.1–17.0), but not AD (HR = 1.0 95% CI: 0.5–2.5).
Conclusions
The association of depression with prevalent MCI and with progression from MCI to dementia, but not with incident MCI, suggests that depression accompanies cognitive impairment but does not precede it.
doi:10.1001/jamaneurol.2013.603
PMCID: PMC3694613  PMID: 23599941
7.  Impaired default network functional connectivity in autosomal dominant Alzheimer disease 
Neurology  2013;81(8):736-744.
Objective:
To investigate default mode network (DMN) functional connectivity MRI (fcMRI) in a large cross-sectional cohort of subjects from families harboring pathogenic presenilin-1 (PSEN1), presenilin-2 (PSEN2), and amyloid precursor protein (APP) mutations participating in the Dominantly Inherited Alzheimer Network.
Methods:
Eighty-three mutation carriers and 37 asymptomatic noncarriers from the same families underwent fMRI during resting state at 8 centers in the United States, United Kingdom, and Australia. Using group-independent component analysis, fcMRI was compared using mutation status and Clinical Dementia Rating to stratify groups, and related to each participant's estimated years from expected symptom onset (eYO).
Results:
We observed significantly decreased DMN fcMRI in mutation carriers with increasing Clinical Dementia Rating, most evident in the precuneus/posterior cingulate and parietal cortices (p < 0.001). Comparison of asymptomatic mutation carriers with noncarriers demonstrated decreased fcMRI in the precuneus/posterior cingulate (p = 0.014) and right parietal cortex (p = 0.0016). We observed a significant interaction between mutation carrier status and eYO, with decreases in DMN fcMRI observed as mutation carriers approached and surpassed their eYO.
Conclusion:
Functional disruption of the DMN occurs early in the course of autosomal dominant Alzheimer disease, beginning before clinically evident symptoms, and worsening with increased impairment. These findings suggest that DMN fcMRI may prove useful as a biomarker across a wide spectrum of disease, and support the feasibility of DMN fcMRI as a secondary endpoint in upcoming multicenter clinical trials in Alzheimer disease.
doi:10.1212/WNL.0b013e3182a1aafe
PMCID: PMC3776464  PMID: 23884042
8.  Genome wide association and linkage analyses identified three loci—4q25, 17q23.2, and 10q11.21—associated with variation in leukocyte telomere length: the Long Life Family Study 
Frontiers in Genetics  2014;4:310.
Leukocyte telomere length is believed to measure cellular aging in humans, and short leukocyte telomere length is associated with increased risks of late onset diseases, including cardiovascular disease, dementia, etc. Many studies have shown that leukocyte telomere length is a heritable trait, and several candidate genes have been identified, including TERT, TERC, OBFC1, and CTC1. Unlike most studies that have focused on genetic causes of chronic diseases such as heart disease and diabetes in relation to leukocyte telomere length, the present study examined the genome to identify variants that may contribute to variation in leukocyte telomere length among families with exceptional longevity. From the genome wide association analysis in 4,289 LLFS participants, we identified a novel intergenic SNP rs7680468 located near PAPSS1 and DKK2 on 4q25 (p = 4.7E-8). From our linkage analysis, we identified two additional novel loci with HLOD scores exceeding three, including 4.77 for 17q23.2, and 4.36 for 10q11.21. These two loci harbor a number of novel candidate genes with SNPs, and our gene-wise association analysis identified multiple genes, including DCAF7, POLG2, CEP95, and SMURF2 at 17q23.2; and RASGEF1A, HNRNPF, ANF487, CSTF2T, and PRKG1 at 10q11.21. Among these genes, multiple SNPs were associated with leukocyte telomere length, but the strongest association was observed with one contiguous haplotype in CEP95 and SMURF2. We also show that three previously reported genes—TERC, MYNN, and OBFC1—were significantly associated with leukocyte telomere length at pempirical < 0.05.
doi:10.3389/fgene.2013.00310
PMCID: PMC3894567  PMID: 24478790
telomere length; aging; familial longevity; genome wide association and linkage; family-based study; novel genes
9.  Different Demographic, Genetic, and Longitudinal Traits in Language versus Memory Alzheimer’s Subgroups 
Journal of Alzheimer's disease : JAD  2013;37(1):10.3233/JAD-130320.
The study’s objective was to compare demographics, APOE genotypes, and rate of rise over time in functional impairment in neuropsychologically defined language, typical, and memory subgroups of clinical Alzheimer’s disease (AD). 1,368 participants from the National Alzheimer’s Coordinating Center database with a diagnosis of probable AD (CDR 0.5–1.0) were included. A language subgroup (n = 229) was defined as having language performance >1 SD worse than memory performance. A memory subgroup (n = 213) was defined as having memory performance >1 SD worse than language performance. A typical subgroup (n = 926) was defined as having a difference in language and memory performance of <1 SD. Compared with the memory subgroup, the language subgroup was 3.7 years older and more frequently self-identified as African American (OR = 3.69). Under a dominant genetic model, the language subgroup had smaller odds of carrying at least one APOEε4 allele relative to the memory subgroup. While this difference was present for all ages, it was more striking at a younger age (OR = 0.19 for youngest tertile; OR = 0.52 for oldest tertile). Compared with the memory subgroup, the language subgroup rose 35% faster on the Functional Assessment Questionnaire and 44% faster on CDR sum of boxes over time. Among a subset of participants who underwent autopsy (n = 98), the language, memory, and typical subgroups were equally likely to have an AD pathologic diagnosis, suggesting that variation in non-AD pathologies across subtypes did not lead to the observed differences. The study demonstrates that a language subgroup of AD has different demographics, genetic profile, and disease course in addition to cognitive phenotype.
doi:10.3233/JAD-130320
PMCID: PMC3877683  PMID: 23788008
African Americans; age of onset; Alzheimer’s disease; aphasia; apolipoprotein E4; focal onset Alzheimer’s disease; demographic factors; language; longitudinal studies; memory
10.  C9ORF72 hexanucleotide repeat expansions in clinical Alzheimer’s disease 
JAMA neurology  2013;70(6):736-741.
Objective
Hexanucleotide repeat expansions in C9ORF72 underlie a significant fraction of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). This study investigates the frequency of C9ORF72 repeat expansions in clinically diagnosed late-onset Alzheimer’s disease (AD).
Design, setting and patients
This case-control study genotyped the C9ORF72 repeat expansion in 872 unrelated familial AD cases and 888 controls recruited as part of the NIA-LOAD cohort, a multi-site collaboration studying 1000 families with two or more individuals clinically diagnosed with late-onset-AD.
Main Outcome Measure
We determined the presence or absence of the C9ORF72 repeat expansion by repeat-primed PCR, the length of the longest non-expanded allele, segregation of the genotype with disease, and clinical features of repeat expansion carriers.
Results
Three families showed large C9ORF72 hexanucleotide repeat expansions. Two additional families carried more than 30 repeats. Segregation with disease could be demonstrated in 3 families. One affected expansion carrier had neuropathology compatible with AD. In the NIA-LOAD series, the C9ORF72 repeat expansions constituted the second most common pathogenic mutation, just behind the PSEN1 A79V mutation, highlighting the heterogeneity of clinical presentations associated with repeat expansions.
Interpretation
C9ORF72 repeat expansions explain a small proportion of patients with a clinical presentation indistinguishable from AD, and highlight the necessity of screening “FTD genes” in clinical AD cases with strong family history.
doi:10.1001/2013.jamaneurol.537
PMCID: PMC3681841  PMID: 23588422
11.  Regional white matter hyperintensity volume, not hippocampal atrophy, predicts incident Alzheimer’s disease in the community 
Archives of neurology  2012;69(12):1621-1627.
Background
New onset Alzheimer’s disease (AD) is often attributed to degenerative changes in the hippocampus. However, the contribution of regionally distributed small vessel cerebrovascular disease, visualized as white matter hyperintensities (WMH) on MRI, remains unclear.
Objective
To determine whether regional WMH and hippocampal volume predict incident AD in an epidemiological study.
Design
A longitudinal community-based epidemiological study of older adults from northern Manhattan.
Setting
The Washington Heights/Inwood Columbia Aging Project
Participants
Between 2005 and 2007, 717 non-demented participants received MRI scans. An average of 40.28 (SD=9.77) months later, 503 returned for follow-up clinical examination and 46 met criteria for incident dementia (45 with AD). Regional WMH and relative hippocampal volumes were derived. Three Cox proportional hazards models were run to predict incident dementia, controlling for relevant variables. The first included all WMH measurements; the second included relative hippocampal volume; and the third combined the two measurements.
Main outcome measures
Incident Alzheimer’s disease.
Results
White matter hyperintensity volume in the parietal lobe predicted time to incident dementia (HR=1.194, p=0.031). Relative hippocampal volume did not predict incident dementia when considered alone (HR=0.419, p=0.768) or with the WMH measures included in the model (HR=0.302, p=0.701). Including hippocampal volume in the model did not notably alter the predictive utility of parietal lobe WMH (HR=1.197, p=0.049).
Conclusion
The findings highlight the regional specificity of the association of WMH with AD. It is not clear whether parietal WMH solely represent a marker for cerebrovascular burden or point to distinct injury compared to other regions. Future work should elucidate pathogenic mechanisms linking WMH and AD pathology.
doi:10.1001/archneurol.2012.1527
PMCID: PMC3597387  PMID: 22945686
Alzheimer’s disease; MRI; cerebrovascular disease; hippocampus
12.  Developing an international network for Alzheimer research: The Dominantly Inherited Alzheimer Network 
Clinical investigation  2012;2(10):975-984.
The Dominantly Inherited Alzheimer Network (DIAN) is a collaborative effort of international Alzheimer disease (AD) centers that are conducting a multifaceted prospective biomarker study in individuals at-risk for autosomal dominant AD (ADAD). DIAN collects comprehensive information and tissue in accordance with standard protocols from asymptomatic and symptomatic ADAD mutation carriers and their non-carrier family members to determine the pathochronology of clinical, cognitive, neuroimaging, and fluid biomarkers of AD. This article describes the structure, implementation, and underlying principles of DIAN, as well as the demographic features of the initial DIAN cohort.
doi:10.4155/cli.12.93
PMCID: PMC3489185  PMID: 23139856
Alzheimer disease; autosomal dominant; biomarkers of Alzheimer disease; PSEN1; PSEN2; APP; amyloid-beta; preclinical Alzheimer disease
13.  Association of Shorter Leukocyte Telomere Repeat Length with Dementia and Mortality 
Archives of neurology  2012;69(10):1332-1339.
Objective
Shortening of chromosomal telomeres is a consequence of cell division, and is a biological factor related to cellular aging and potentially to more rapid organismal biological aging. We have hypothesized that shorter telomere length, as measured in human blood samples, is associated with the development of Alzheimer disease, and with mortality.
Design/Setting
Using data from a multiethnic community-based study of aging and dementia, we studied 1,983 subjects over age 65 yr, who had available stored leukocyte DNA. Mean age-at-blood-draw was 78.3 ± 6.9 yr. Mean age of death was 86.0 ± 7.4 yr. Median follow-up for mortality was 9.3 yr; 190 (9.6%) developed incident dementia. We used real-time PCR to determine mean telomere length (TL) in a modified telomere-sequence to single-copy-gene-sequence ratio method.
Results
TL was inversely related to age, and shorter in men than women. Persons dying during follow-up had shorter TL compared to survivors (6,218±819 vs. 6,491±881 basepairs, p<0.0001) even after adjustment for age, sex, education, and APOE genotype. Individuals who developed dementia had significantly shorter TL (6,131±798 for prevalent cases, and 6,315±817 for incident cases) compared with those remaining dementia-free (6,431±864). Cox-regression analyses showed that shorter TL was a risk for earlier onset of dementia (p=0.05), but stratified analyses for sex showed that this association of age-at-onset of dementia with shorter TL was significant in women, but not in men.
Conclusions
Our findings suggest that shortened leukocyte TL is associated with risks of dementia and mortality, and may therefore be a marker of biological aging.
doi:10.1001/archneurol.2012.1541
PMCID: PMC3622729  PMID: 22825311
biological aging; Alzheimer's disease; apolipoprotein E; leukocyte; DNA
14.  Analysis of Copy Number Variation in Alzheimer’s Disease: the NIA-LOAD/NCRAD Family Study 
Current Alzheimer research  2012;9(7):801-814.
Copy number variants (CNVs) are DNA regions that have gains (duplications) or losses (deletions) of genetic material. CNVs may encompass a single gene or multiple genes and can affect their function. They are hypothesized to play an important role in certain diseases. We previously examined the role of CNVs in late-onset Alzheimer's disease (AD) and mild cognitive impairment (MCI) using participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study and identified gene regions overlapped by CNVs only in cases (AD and/or MCI) but not in controls. Using a similar approach as ADNI, we investigated the role of CNVs using 794 AD and 196 neurologically evaluated control non-Hispanic Caucasian NIA-LOAD/NCRAD Family Study participants with DNA derived from blood/brain tissue. The controls had no family history of AD and were unrelated to AD participants. CNV calls were generated and analyzed after detailed quality review. 711 AD cases and 171 controls who passed all quality thresholds were included in case/control association analyses, focusing on candidate gene and genome-wide approaches. We identified genes overlapped by CNV calls only in AD cases but not controls. A trend for lower CNV call rate was observed for deletions as well as duplications in cases compared to controls. Gene-based association analyses confirmed previous findings in the ADNI study (ATXN1, HLA-DPB1, RELN, DOPEY2, GSTT1, CHRFAM7A, ERBB4, NRXN1) and identified a new gene (IMMP2L) that may play a role in AD susceptibility. Replication in independent samples as well as further analyses of these gene regions is warranted.
PMCID: PMC3500615  PMID: 22486522
Alzheimer's disease; association study; CHRFAM7A; copy number variation; dementia; IMMP2L; NIA-LOAD/NCRAD; replication
15.  Screening for C9ORF72 repeat expansion in FTLD 
Neurobiology of aging  2012;33(8):1850.e1-1850.11.
In the present study we aimed to determine the prevalence of C9ORF72 GGGGCC hexanucleotide expansion in our cohort of 53 FTLD patients and 174 neurologically normal controls. We identified the hexanucleotide repeat, in the pathogenic range, in 4 (2 bv-FTD and 2 FTD-ALS) out of 53 patients and one neurologically normal control. Interestingly, two of the C9ORF72 expansion carriers also carried two novel missense mutations in GRN (Y294C) and in PSEN-2 (I146V). Further, one of the C9ORF72 expansion carriers, for whom pathology was available, showed amyloid plaques and tangles in addition to TDP-43 pathology. In summary, our findings suggest that the hexanucleotide expansion is probably associated with ALS, FTD or FTD-ALS and occasional comorbid conditions such as Alzheimer’s disease. These findings are novel and need to be cautiously interpreted and most importantly replicated in larger numbers of samples.
doi:10.1016/j.neurobiolaging.2012.02.017
PMCID: PMC3743244  PMID: 22459598
FTLD; bv-FTD; FTD-ALS; C9ORF72; GRN; PSEN-2; Alzheimer’s disease
16.  Novel late-onset Alzheimer disease loci variants associate with brain gene expression 
Neurology  2012;79(3):221-228.
Objective:
Recent genome-wide association studies (GWAS) of late-onset Alzheimer disease (LOAD) identified 9 novel risk loci. Discovery of functional variants within genes at these loci is required to confirm their role in Alzheimer disease (AD). Single nucleotide polymorphisms that influence gene expression (eSNPs) constitute an important class of functional variants. We therefore investigated the influence of the novel LOAD risk loci on human brain gene expression.
Methods:
We measured gene expression levels in the cerebellum and temporal cortex of autopsied AD subjects and those with other brain pathologies (∼400 total subjects). To determine whether any of the novel LOAD risk variants are eSNPs, we tested their cis-association with expression of 6 nearby LOAD candidate genes detectable in human brain (ABCA7, BIN1, CLU, MS4A4A, MS4A6A, PICALM) and an additional 13 genes ±100 kb of these SNPs. To identify additional eSNPs that influence brain gene expression levels of the novel candidate LOAD genes, we identified SNPs ±100 kb of their location and tested for cis-associations.
Results:
CLU rs11136000 (p = 7.81 × 10−4) and MS4A4A rs2304933/rs2304935 (p = 1.48 × 10−4–1.86 × 10−4) significantly influence temporal cortex expression levels of these genes. The LOAD-protective CLU and risky MS4A4A locus alleles associate with higher brain levels of these genes. There are other cis-variants that significantly influence brain expression of CLU and ABCA7 (p = 4.01 × 10−5–9.09 × 10−9), some of which also associate with AD risk (p = 2.64 × 10−2–6.25 × 10−5).
Conclusions:
CLU and MS4A4A eSNPs may at least partly explain the LOAD risk association at these loci. CLU and ABCA7 may harbor additional strong eSNPs. These results have implications in the search for functional variants at the novel LOAD risk loci.
doi:10.1212/WNL.0b013e3182605801
PMCID: PMC3398432  PMID: 22722634
17.  Faster Cognitive and Functional Decline in Dysexecutive versus Amnestic Alzheimer's Subgroups: A Longitudinal Analysis of the National Alzheimer's Coordinating Center (NACC) Database 
PLoS ONE  2013;8(6):e65246.
Objective
To compare the rate of cognitive and functional decline in dysexecutive, typical and amnestic subgroups of Alzheimer’s disease.
Methods
943 participants from the National Alzheimer’s Coordinating Center (NACC) database who had a diagnosis of probable AD were followed for a mean of 2.3 years. A dysexecutive subgroup (n = 165) was defined as having executive performance >1.5 SD worse than memory performance, an amnestic subgroup (n = 157) was defined as having memory performance >1.5 SD worse than executive performance and a typical subgroup (n = 621) was defined as having a difference in executive and memory performance of <1.5 SD. Generalized estimating equations (GEE) were used to model decline on the Folstein Mini Mental Status Exam (MMSE), rise on the Clinical Dementia Rating (CDR) sum of boxes and rise on the total Functional Assessment Questionnaire (FAQ).
Results
Compared with the amnestic subgroup, the dysexecutive subgroup declined 2.2X faster on the Folstein MMSE (p<.001), rose 42% faster on the CDR sum of boxes (p = .03) and rose 33% faster on the total FAQ (p = .01). Rate of change for the typical subgroup fell between that of the amnestic and dysexecutive subgroups for the MMSE, CDR sum of boxes and total FAQ. Among a subset of participants (n = 129) who underwent autopsy, the dysexecutive, amnestic and typical subgroups did not differ in odds of having an AD pathologic diagnosis, suggesting that variation in non-AD pathologies across subtypes did not lead to the observed differences.
Conclusions
A dysexecutive subgroup of AD has a unique disease course in addition to cognitive phenotype.
doi:10.1371/journal.pone.0065246
PMCID: PMC3670903  PMID: 23755200
18.  Genome-wide Association Study of Alzheimer’s disease with Psychotic Symptoms 
Molecular psychiatry  2011;17(12):1316-1327.
Psychotic symptoms occur in approximately 40% of subjects with Alzheimer’s disease (AD) and are associated with more rapid cognitive decline and increased functional deficits. They show heritability up to 61% and have been proposed as a marker for a disease subtype suitable for gene mapping efforts. We undertook a combined analysis of three genome-wide association studies (GWAS) to identify loci that a) increase susceptibility to an AD and subsequent psychotic symptoms; or b) modify risk of psychotic symptoms in the presence of neurodegeneration caused by AD. 1299 AD cases with psychosis (AD+P), 735 AD cases without psychosis (AD-P) and 5659 controls were drawn from GERAD1, the NIA-LOAD family study and the University of Pittsburgh ADRC GWAS. Unobserved genotypes were imputed to provide data on > 1.8 million SNPs. Analyses in each dataset were completed comparing a) AD+P to AD-P cases, and b) AD+P cases with controls (GERAD1, ADRC only). Aside from the APOE locus, the strongest evidence for association was observed in an intergenic region on chromosome 4 (rs753129; ‘AD+PvAD-P’ P=2.85 × 10−7; ‘AD+PvControls’ P=1.11 × 10−4). SNPs upstream of SLC2A9 (rs6834555, P=3.0×10−7) and within VSNL1 (rs4038131, P=5.9×10−7) showed strongest evidence for association with AD+P when compared to controls. These findings warrant further investigation in larger, appropriately powered samples in which the presence of psychotic symptoms in AD has been well characterised.
doi:10.1038/mp.2011.125
PMCID: PMC3272435  PMID: 22005930
Alzheimer’s disease; psychosis; behavioural symptoms; genome-wide association study; genetic
19.  Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis 
Whitcomb, David C. | LaRusch, Jessica | Krasinskas, Alyssa M. | Klei, Lambertus | Smith, Jill P. | Brand, Randall E. | Neoptolemos, John P. | Lerch, Markus M. | Tector, Matt | Sandhu, Bimaljit S. | Guda, Nalini M. | Orlichenko, Lidiya | Alkaade, Samer | Amann, Stephen T. | Anderson, Michelle A. | Baillie, John | Banks, Peter A. | Conwell, Darwin | Coté, Gregory A. | Cotton, Peter B. | DiSario, James | Farrer, Lindsay A. | Forsmark, Chris E. | Johnstone, Marianne | Gardner, Timothy B. | Gelrud, Andres | Greenhalf, William | Haines, Jonathan L. | Hartman, Douglas J. | Hawes, Robert A. | Lawrence, Christopher | Lewis, Michele | Mayerle, Julia | Mayeux, Richard | Melhem, Nadine M. | Money, Mary E. | Muniraj, Thiruvengadam | Papachristou, Georgios I. | Pericak-Vance, Margaret A. | Romagnuolo, Joseph | Schellenberg, Gerard D. | Sherman, Stuart | Simon, Peter | Singh, Vijay K. | Slivka, Adam | Stolz, Donna | Sutton, Robert | Weiss, Frank Ulrich | Wilcox, C. Mel | Zarnescu, Narcis Octavian | Wisniewski, Stephen R. | O'Connell, Michael R. | Kienholz, Michelle L. | Roeder, Kathryn | Barmada, M. Michael | Yadav, Dhiraj | Devlin, Bernie | Albert, Marilyn S. | Albin, Roger L. | Apostolova, Liana G. | Arnold, Steven E. | Baldwin, Clinton T. | Barber, Robert | Barnes, Lisa L. | Beach, Thomas G. | Beecham, Gary W. | Beekly, Duane | Bennett, David A. | Bigio, Eileen H. | Bird, Thomas D. | Blacker, Deborah | Boxer, Adam | Burke, James R. | Buxbaum, Joseph D. | Cairns, Nigel J. | Cantwell, Laura B. | Cao, Chuanhai | Carney, Regina M. | Carroll, Steven L. | Chui, Helena C. | Clark, David G. | Cribbs, David H. | Crocco, Elizabeth A. | Cruchaga, Carlos | DeCarli, Charles | Demirci, F. Yesim | Dick, Malcolm | Dickson, Dennis W. | Duara, Ranjan | Ertekin-Taner, Nilufer | Faber, Kelley M. | Fallon, Kenneth B. | Farlow, Martin R. | Ferris, Steven | Foroud, Tatiana M. | Frosch, Matthew P. | Galasko, Douglas R. | Ganguli, Mary | Gearing, Marla | Geschwind, Daniel H. | Ghetti, Bernardino | Gilbert, John R. | Gilman, Sid | Glass, Jonathan D. | Goate, Alison M. | Graff-Radford, Neill R. | Green, Robert C. | Growdon, John H. | Hakonarson, Hakon | Hamilton-Nelson, Kara L. | Hamilton, Ronald L. | Harrell, Lindy E. | Head, Elizabeth | Honig, Lawrence S. | Hulette, Christine M. | Hyman, Bradley T. | Jicha, Gregory A. | Jin, Lee-Way | Jun, Gyungah | Kamboh, M. Ilyas | Karydas, Anna | Kaye, Jeffrey A. | Kim, Ronald | Koo, Edward H. | Kowall, Neil W. | Kramer, Joel H. | Kramer, Patricia | Kukull, Walter A. | LaFerla, Frank M. | Lah, James J. | Leverenz, James B. | Levey, Allan I. | Li, Ge | Lin, Chiao-Feng | Lieberman, Andrew P. | Lopez, Oscar L. | Lunetta, Kathryn L. | Lyketsos, Constantine G. | Mack, Wendy J. | Marson, Daniel C. | Martin, Eden R. | Martiniuk, Frank | Mash, Deborah C. | Masliah, Eliezer | McKee, Ann C. | Mesulam, Marsel | Miller, Bruce L. | Miller, Carol A. | Miller, Joshua W. | Montine, Thomas J. | Morris, John C. | Murrell, Jill R. | Naj, Adam C. | Olichney, John M. | Parisi, Joseph E. | Peskind, Elaine | Petersen, Ronald C. | Pierce, Aimee | Poon, Wayne W. | Potter, Huntington | Quinn, Joseph F. | Raj, Ashok | Raskind, Murray | Reiman, Eric M. | Reisberg, Barry | Reitz, Christiane | Ringman, John M. | Roberson, Erik D. | Rosen, Howard J. | Rosenberg, Roger N. | Sano, Mary | Saykin, Andrew J. | Schneider, Julie A. | Schneider, Lon S. | Seeley, William W. | Smith, Amanda G. | Sonnen, Joshua A. | Spina, Salvatore | Stern, Robert A. | Tanzi, Rudolph E. | Trojanowski, John Q. | Troncoso, Juan C. | Tsuang, Debby W. | Valladares, Otto | Van Deerlin, Vivianna M. | Van Eldik, Linda J. | Vardarajan, Badri N. | Vinters, Harry V. | Vonsattel, Jean Paul | Wang, Li-San | Weintraub, Sandra | Welsh-Bohmer, Kathleen A. | Williamson, Jennifer | Woltjer, Randall L. | Wright, Clinton B. | Younkin, Steven G. | Yu, Chang-En | Yu, Lei
Nature genetics  2012;44(12):1349-1354.
Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1×10-12) and x-linked CLDN2 (p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07.
doi:10.1038/ng.2466
PMCID: PMC3510344  PMID: 23143602
20.  Meta-analysis of Parkinson disease: Identification of a novel locus, RIT2 
Annals of Neurology  2012;71(3):370-384.
Objective
Genome-wide association (GWAS) methods have identified genes contributing to Parkinson disease (PD); we sought to identify additional genes associated with PD susceptibility.
Methods
A two stage design was used. First, individual level genotypic data from five recent PD GWAS (Discovery Sample: 4,238 PD cases and 4,239 controls) were combined. Following imputation, a logistic regression model was employed in each dataset to test for association with PD susceptibility and results from each dataset were meta-analyzed. Second, 768 SNPs were genotyped in an independent Replication Sample (3,738 cases and 2,111 controls).
Results
Genome-wide significance was reached for SNPs in SNCA (rs356165, G: odds ratio (OR)=1.37; p=9.3 × 10−21), MAPT (rs242559, C: OR=0.78; p=1.5 × 10−10), GAK/DGKQ (rs11248051, T:OR=1.35; p=8.2 × 10−9/ rs11248060, T: OR=1.35; p=2.0×10−9), and the HLA region (rs3129882, A: OR=0.83; p=1.2 × 10−8), which were previously reported. The Replication Sample confirmed the associations with SNCA, MAPT, and the HLA region and also with GBA (E326K OR=1.71; p=5 × 10−8 Combined Sample) (N370 OR=3.08; p=7 × 10−5 Replication sample). A novel PD susceptibility locus, RIT2, on chromosome 18 (rs12456492; p=5 × 10−5 Discovery Sample; p=1.52 × 10−7 Replication sample; p=2 × 10−10 Combined Sample) was replicated. Conditional analyses within each of the replicated regions identified distinct SNP associations within GBA and SNCA, suggesting that there may be multiple risk alleles within these genes.
Interpretation
We identified a novel PD susceptibility locus, RIT2, replicated several previously identified loci, and identified more than one risk allele within SNCA and GBA.
doi:10.1002/ana.22687
PMCID: PMC3354734  PMID: 22451204
21.  Clinical and Biomarker Changes in Dominantly Inherited Alzheimer’s Disease 
The New England journal of medicine  2012;367(9):795-804.
BACKGROUND
The order and magnitude of pathologic processes in Alzheimer’s disease are not well understood, partly because the disease develops over many years. Autosomal dominant Alzheimer’s disease has a predictable age at onset and provides an opportunity to determine the sequence and magnitude of pathologic changes that culminate in symptomatic disease.
METHODS
In this prospective, longitudinal study, we analyzed data from 128 participants who underwent baseline clinical and cognitive assessments, brain imaging, and cerebrospinal fluid (CSF) and blood tests. We used the participant’s age at baseline assessment and the parent’s age at the onset of symptoms of Alzheimer’s disease to calculate the estimated years from expected symptom onset (age of the participant minus parent’s age at symptom onset). We conducted cross-sectional analyses of baseline data in relation to estimated years from expected symptom onset in order to determine the relative order and magnitude of pathophysiological changes.
RESULTS
Concentrations of amyloid-beta (Aβ)42 in the CSF appeared to decline 25 years before expected symptom onset. Aβ deposition, as measured by positron-emission tomography with the use of Pittsburgh compound B, was detected 15 years before expected symptom onset. Increased concentrations of tau protein in the CSF and an increase in brain atrophy were detected 15 years before expected symptom onset. Cerebral hypometabolism and impaired episodic memory were observed 10 years before expected symptom onset. Global cognitive impairment, as measured by the Mini–Mental State Examination and the Clinical Dementia Rating scale, was detected 5 years before expected symptom onset, and patients met diagnostic criteria for dementia at an average of 3 years after expected symptom onset.
CONCLUSIONS
We found that autosomal dominant Alzheimer’s disease was associated with a series of pathophysiological changes over decades in CSF biochemical markers of Alzheimer’s disease, brain amyloid deposition, and brain metabolism as well as progressive cognitive impairment. Our results require confirmation with the use of longitudinal data and may not apply to patients with sporadic Alzheimer’s disease. (Funded by the National Institute on Aging and others; DIAN ClinicalTrials.gov number, NCT00869817.)
doi:10.1056/NEJMoa1202753
PMCID: PMC3474597  PMID: 22784036
22.  Comprehensive Search for Alzheimer Disease Susceptibility Loci in the APOE Region 
Archives of neurology  2012;69(10):1270-1279.
Objective
To evaluate the association of risk and age at onset (AAO) of Alzheimer disease (AD) with single-nucleotide polymorphisms (SNPs) in the chromosome 19 region including apolipoprotein E (APOE) and a repeat-length polymorphism in TOMM40 (poly-T, rs10524523).
Design
Conditional logistic regression models and survival analysis.
Setting
Fifteen genome-wide association study data sets assembled by the Alzheimer's Disease Genetics Consortium.
Participants
Eleven thousand eight hundred forty AD cases and 10 931 cognitively normal elderly controls.
Main Outcome Measures
Association of AD risk and AAO with genotyped and imputed SNPs located in an 800-Mb region including APOE in the entire Alzheimer's Disease Genetics Consortium data set and with the TOMM40 poly-T marker genotyped in a subset of 1256 cases and 1605 controls.
Results
In models adjusting for APOE ε4, no SNPs in the entire region were significantly associated with AAO at P<.001. Rs10524523 was not significantly associated with AD or AAO in models adjusting for APOE genotype or within the subset of ε3/ε3 subjects.
Conclusions
APOE alleles ε2, ε3, and ε4 account for essentially all the inherited risk of AD associated with this region. Other variants including a poly-T track in TOMM40 are not independent risk or AAO loci.
doi:10.1001/archneurol.2012.2052
PMCID: PMC3579659  PMID: 22869155
23.  Role of p73 in Alzheimer disease: lack of association in mouse models or in human cohorts 
Background
P73 belongs to the p53 family of cell survival regulators with the corresponding locus Trp73 producing the N-terminally distinct isoforms, TAp73 and DeltaNp73. Recently, two studies have implicated the murine Trp73 in the modulation in phospho-tau accumulation in aged wild type mice and in young mice modeling Alzheimer’s disease (AD) suggesting that Trp73, particularly the DeltaNp73 isoform, links the accumulation of amyloid peptides to the creation of neurofibrillary tangles (NFTs). Here, we reevaluated tau pathologies in the same TgCRND8 mouse model as the previous studies.
Results
Despite the use of the same animal models, our in vivo studies failed to demonstrate biochemical or histological evidence for misprocessing of tau in young compound Trp73+/- + TgCRND8 mice or in aged Trp73+/- mice analyzed at the ages reported previously, or older. Secondly, we analyzed an additional mouse model where the DeltaNp73 was specifically deleted and confirmed a lack of impact of the DeltaNp73 allele, either in heterozygous or homozygous form, upon tau pathology in aged mice. Lastly, we also examined human TP73 for single nucleotide polymorphisms (SNPs) and/or copy number variants in a meta-analysis of 10 AD genome-wide association datasets. No SNPs reached significance after correction for multiple testing and no duplications/deletions in TP73 were found in 549 cases of AD and 544 non-demented controls.
Conclusion
Our results fail to support P73 as a contributor to AD pathogenesis.
doi:10.1186/1750-1326-8-10
PMCID: PMC3614544  PMID: 23414597
P73; Alzheimer’s disease; Animal models; GWAS
24.  Replication of the association between variants in the IDE-KIF11-HHEX harboring region on chromosome 10q and plasma amyloid β levels in Alzheimer’s disease 
Neurobiology of aging  2010;33(1):199.e13-199.e17.
Background and Objective
Genetic linkage and association studies in late-onset Alzheimer’s disease (LOAD) or LOAD endophenotypes have pointed to several candidate regions on chromosome 10q, among these the ~250kb LD block harboring the three genes IDE, KIF11 and HHEX. We explored the association between variants in the genomic region harboring the IDE-KIF11-HHEX complex with plasma Aβ40 and Aβ42 levels in a case-control cohort of Caribbean Hispanics.
Methods
First, we performed single marker multivariate linear regression analysis relating the individual SNPs with plasma Aβ40 and Aβ42 levels. Then we performed 3-SNP sliding window haplotype analyses, correcting all analyses for multiple testing
Results
Out of 32 SNPs in this region, three SNPs in IDE (rs2421943, rs12264682, rs11187060) were significantly associated with plasma Aß40 or Aß42 levels in single marker and haplotype analyses after correction for multiple testing. As described above, all these SNPs lie within the same linkage disequilibrium block, and are in linkage disequilibrium with the previously reported haplotypes.
Conclusion
Our findings provide modest support for an association in the IDE harboring region on chromosome 10q with Aβ 40 and 42 levels.
doi:10.1016/j.neurobiolaging.2010.07.005
PMCID: PMC3117070  PMID: 20724036
amyloid beta; Alzheimer’s disease; genetics; insulin-degrading enzyme
25.  Genetic Variants in the Fat and Obesity Associated (FTO) Gene and Risk of Alzheimer's Disease 
PLoS ONE  2012;7(12):e50354.
Background
Recent studies showed that polymorphisms in the Fat and Obesity-Associated (FTO) gene have robust effects on obesity, obesity-related traits and endophenotypes associated with Alzheimer's disease (AD).
Methods
We used 1,877 Caucasian cases and controls from the NIA-LOAD study and 1,093 Caribbean Hispanics to further explore the association of FTO with AD. Using logistic regression, we assessed 42 SNPs in introns 1 and 2, the region previously reported to be associated with AD endophenotypes, which had been derived by genome-wide screenings. In addition, we performed gene expression analyses of neuropathologically confirmed AD cases and controls of two independent datasets (19 AD cases, 10 controls; 176 AD cases, 188 controls) using within- and between-group factors ANOVA of log10 transformed rank invariant normalized expression data.
Results
In the NIALOAD study, one SNP was significantly associated with AD and three additional markers were close to significance (rs6499640, rs10852521, rs16945088, rs8044769, FDR p-value: 0.050.9) with the previously reported SNPs. In the Caribbean Hispanic dataset, we identified three SNPs (rs17219084, rs11075996, rs11075997, FDR p-value: 0.009
Conclusions
Our data support the notion that genetic variation in Introns 1 and 2 of the FTO gene may contribute to AD risk.
doi:10.1371/journal.pone.0050354
PMCID: PMC3520931  PMID: 23251365

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