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© 2015, Elsevier Inc. All rights reserved. Background: Late-onset Alzheimer's disease (AD) is heritable with 20 genes showing genome-wide association in the International Genomics of Alzheimer's Project (IGAP). To identify the biology underlying the disease, we extended these genetic data in a pathway analysis. Methods: The ALIGATOR and GSEA algorithms were used in the IGAP data to identify associated functional pathways and correlated gene expression networks in human brain. Results: ALIGATOR identified an excess of curated biological pathways showing enrichment of association. Enriched areas of biology included the immune response (P = 3.27 × 10-12 after multiple testing correction for pathways), regulation of endocytosis (P = 1.31 × 10-11), cholesterol transport (P = 2.96 × 10-9), and proteasome-ubiquitin activity (P = 1.34 × 10-6). Correlated gene expression analysis identified four significant network modules, all related to the immune response (corrected P =.002-.05). Conclusions: The immune response, regulation of endocytosis, cholesterol transport, and protein ubiquitination represent prime targets for AD therapeutics., Medical Research Council, Alzheimer’s Research UK, and theWelsh Assembly Government. ADGC and CHARGE were supported by the National Institutes of Health, National Institute on Aging (NIH-NIA). CHARGE was also supported by Erasmus Medical Center and Erasmus University. IGAP was funded by the French National Foundation on Alzheimer’s Disease and Related Disorders, the Centre National de Genotypage and the Institut Pasteur de Lille, Inserm, FRC (Fondation pour la Recherche sur le Cerveau), and Rotary. This work has been developed and supported by the LABEX (Laboratory of Excellence Program Investment for the Future) DISTALZ grant (Development of Innovative Strategies for a Transdisciplinary approach to ALZheimer’s disease).

The American Psychiatric Association estimates that 3 to 7 per cent of all school aged children are diagnosed with attention deficit hyperactivity disorder (ADHD). Even after correcting for general cognitive ability, numerous studies report a negative association between ADHD and educational achievement. With polygenic scores we examined whether genetic variants that have a positive influence on educational attainment have a protective effect against ADHD. The effect sizes from a large GWA meta-analysis of educational attainment in adults were used to calculate polygenic scores in an independent sample of 12-year-old children from the Netherlands Twin Register. Linear mixed models showed that the polygenic scores significantly predicted educational achievement, school performance, ADHD symptoms and attention problems in children. These results confirm the genetic overlap between ADHD and educational achievement, indicating that one way to gain insight into genetic variants responsible for variation in ADHD is to include data on educational achievement, which are available at a larger scale. (C) 2014 Wiley Periodicals, Inc.

Epistasis between interleukin-10 (IL10) and aromatase gene polymorphisms has previously been reported to modify the risk of Alzheimer's disease (AD). However, although the main effects of aromatase variants suggest a sex-specific effect in AD, there has been insufficient power to detect sex-specific epistasis between these genes to date. Here we used the cohort of 1757 AD patients and 6294 controls in the Epistasis Project. We replicated the previously reported main effects of aromatase polymorphisms in AD risk in women, for example, adjusted odds ratio of disease for rs1065778 GG = 1.22 (95% confidence interval: 1.01-1.48, P=0.03). We also confirmed a reported epistatic interaction between IL10 rs1800896 and aromatase (CYP19A1) rs1062033, again only in women: adjusted synergy factor = 1.94 (1.16-3.25, 0.01). Aromatase, a rate-limiting enzyme in the synthesis of estrogens, is expressed in AD-relevant brain regions,and is downregulated during the disease. IL-10 is an anti-inflammatory cytokine. Given that estrogens have neuroprotective and anti-inflammatory activities and regulate microglial cytokine production, epistasis is biologically plausible. Diminishing serum estrogen in postmenopausal women, coupled with suboptimal brain estrogen synthesis, may contribute to the inflammatory state, that is a pathological hallmark of AD.

Background Prospective national screening and surveillance programmes serve a range of public health functions. Objectively determining their adequacy and impact on disease may be problematic for rare disorders. We undertook to assess whether objective measures of disease surveillance intensity could be developed for the rare disorder sporadic Creutzfeldt–Jakob disease (CJD) and whether such measures correlate with disease incidence. Method From 10 countries with national human prion disease surveillance centres, the annual number of suspected prion disease cases notified to each national unit (n=17 610), referrals for cerebrospinal fluid (CSF) 14-3-3 protein diagnostic testing (n=28 780) and the number of suspect cases undergoing diagnostic neuropathological examination (n=4885) from 1993 to 2006 were collected. Age and survey year adjusted incidence rate ratios with 95% CIs were estimated using Poisson regression models to assess risk factors for sporadic, non-sporadic and all prion disease cases. Results Age and survey year adjusted analysis showed all three surveillance intensity measures (suspected human prion disease notifications, 14-3-3 protein diagnostic test referrals and neuropathological examinations of suspect cases) significantly predicted the incidence of sporadic CJD, non-sporadic CJD and all prion disease. Conclusions Routine national surveillance methods adjusted as population rates allow objective determination of surveillance intensity, which correlates positively with reported incidence for human prion disease, especially sporadic CJD, largely independent of national context. The predictive relationship between surveillance intensity and disease incidence should facilitate more rapid delineation of aberrations in disease occurrence and assessment of the adequacy of disease monitoring by national registries.

Effective prevention of Alzheimer's disease (AD) requires the development of risk prediction tools permitting preclinical intervention. We constructed a genetic risk score (GRS) comprising common genetic variants associated with AD, evaluated its association with incident AD and assessed its capacity to improve risk prediction over traditional models based on age, sex, education, and APOE epsilon 4. In eight prospective cohorts included in the International Genomics of Alzheimer's Project (IGAP), we derived weighted sum of risk alleles from the 19 top SNPs reported by the IGAPGWAS in participants aged 65 and older without prevalent dementia. Hazard ratios (HR) of incident AD were estimated in Cox models. Improvement in risk prediction was measured by the difference in C-index (Delta-C), the integrated discrimination improvement (IDI) and continuous net reclassification improvement (NRI>0). Overall, 19,687 participants at risk were included, of whom 2,782 developed AD. The GRS was associated with a 17% increase in AD risk (pooled HR=1.17; 95% CI = [1.13-1.21] per standard deviation increase in GRS; p-value = 2.86x10(-16)). This association was stronger among persons with at least one APOE epsilon 4 allele (HRGRS = 1.24; 95% CI = [1.15-1.34]) than in others (HRGRS = 1.13; 95% CI = [1.08-1.18]; p(interaction) = 3.45x10(-2)). Risk prediction after seven years of follow-up showed a small improvement when adding the GRS to age, sex, APOE epsilon 4, and education (Delta-Cindex = 0.0043 [0.0019-0.0067]). Similar patterns were observed for IDI and NRI>0. In conclusion, a risk score incorporating common genetic variation outside the APOE epsilon 4 locus improved AD risk prediction and may facilitate risk stratification for prevention trials.

We performed an exome-wide association analysis in 1393 late-onset Alzheimer’s disease (LOAD) cases and 8141 controls from the CHARGE consortium. We found that a rare variant (P155L) in TM2D3 was enriched in Icelanders (~0.5% versus, Author Summary Alzheimer’s disease (AD) is the most common cause of dementia in the older adult population. There is substantial evidence for an important genetic contribution to AD risk. While prior work has comprehensively evaluated the contribution of common genetic variants in large population-based cohorts, the role of rare variants remains to be defined. Here, we have used a newer genotyping array to characterize less common variants, including those likely to impact the function of encoded proteins, in a combined cohort of 1393 AD cases and 8141 control subjects without AD. Our results implicate a novel, amino acid-changing variant, P155L, in the TM2D3 gene. This variant was discovered to be more common in the Icelandic population, where it was significantly associated with both increased risk and earlier age of onset of AD. Lastly, in order to examine the potential functional impact of the implicated variant, we performed additional studies in the fruit fly. Our results suggest that P155L causes a loss-of-function in TM2D3, in the context of Notch-Presenilin signal transduction. In sum, we identify a novel, rare TM2D3 variant in association with AD risk and highlight functional connections with AD-relevant biology.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field. BACKGROUND: Sequence variants, including the ε4 allele of apolipoprotein E, have been associated with the risk of the common late-onset form of Alzheimer's disease. Few rare variants affecting the risk of late-onset Alzheimer's disease have been found. METHODS: We obtained the genome sequences of 2261 Icelanders and identified sequence variants that were likely to affect protein function. We imputed these variants into the genomes of patients with Alzheimer's disease and control participants and then tested for an association with Alzheimer's disease. We performed replication tests using case-control series from the United States, Norway, The Netherlands, and Germany. We also tested for a genetic association with cognitive function in a population of unaffected elderly persons. RESULTS: A rare missense mutation (rs75932628-T) in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2), which was predicted to result in an R47H substitution, was found to confer a significant risk of Alzheimer's disease in Iceland (odds ratio, 2.92; 95% confidence interval [CI], 2.09 to 4.09; P=3.42×10(-10)). The mutation had a frequency of 0.46% in controls 85 years of age or older. We observed the association in additional sample sets (odds ratio, 2.90; 95% CI, 2.16 to 3.91; P=2.1×10(-12) in combined discovery and replication samples). We also found that carriers of rs75932628-T between the ages of 80 and 100 years without Alzheimer's disease had poorer cognitive function than noncarriers (P=0.003). CONCLUSIONS: Our findings strongly implicate variant TREM2 in the pathogenesis of Alzheimer's disease. Given the reported antiinflammatory role of TREM2 in the brain, the R47H substitution may lead to an increased predisposition to Alzheimer's disease through impaired containment of inflammatory processes. (Funded by the National Institute on Aging and others.). Research Council of Norway National Institute on Aging P50-AG025688 U01AG006781 South-Eastern Norway Health Authority National Institutes of Health U01HG004438 National Human Genome Research Institute U01HG004610 eMERGE Administrative Coordinating Center U01HG004603 National Center for Biotechnology Information Erasmus Medical Center Erasmus University, Rotterdam Netherlands Organization for Health Research and Development Research Institute for Diseases in the Elderly Ministry of Education, Culture and Science Ministry for Health, Welfare and Sports Municipality of Rotterdam Research Institute for Diseases in the Elderly 014-93-015 Stichting Alzheimer Onder-zoek Hersenstichting Nederland Netherlands Genomics Initiative-Netherlands Organization for Scientific Research (Center for Medical Systems Biology and the Netherlands Consortium for Healthy Aging) info:eu-repo/grantAgreement/EC/FP7/201413

Item does not contain fulltext Plasma concentrations of Abeta40 and Abeta42 rise with age and are increased in people with mutations that cause early-onset Alzheimer's disease (AD). Amyloid beta (Abeta) plasma levels were successfully used as an (endo)phenotype for gene discovery using a linkage approach in families with dominant forms of disease. Here, we searched for loci involved in Abeta plasma levels in a series of non-demented patients with hypertension in the Erasmus Rucphen Family study. Abeta40 and Abeta42 levels were determined in 125 subjects with severe hypertension. All patients were genotyped with a 6,000 single nucleotide polymorphisms (SNPs) illumina array designed for linkage analysis. We conducted linkage analysis of plasma Abeta levels. None of the linkage analyses yielded genome-wide significant logarithm of odds (LOD) score over 3.3, but there was suggestive evidence for linkage (LOD > 1.9) for two regions: 1q41 (LOD = 2.07) and 11q14.3 (LOD = 2.97), both for Abeta40. These regions were followed up with association analysis in the study subjects and in 320 subjects from a population-based cohort. For the Abeta40 region on chromosome 1, association of several SNPs was observed at the presenilin 2 gene (PSEN2) (p = 2.58 x 10(-4) for rs6703170). On chromosome 11q14-21, we found some association (p = 3.1 x 10(-3) for rs2514299). This linkage study of plasma concentrations of Abeta40 and Abeta42 yielded two suggestive regions, of which one points toward a known locus for familial AD.

Contains fulltext : 108169.pdf (Publisher’s version ) (Open Access) Prion diseases are rare and fatal neurodegenerative disorders that can be sporadic, inherited or acquired by infection. Based on a national surveillance program in the Netherlands we describe here the clinical, neuropathological, genetic and molecular characteristics of 162 patients with neuropathologically confirmed prion disease over a 12-year period (1998-2009). Since 1998, there has been a relatively stable mortality of Creutzfeldt-Jakob disease (CJD) in the Netherlands, ranging from 0.63 to 1.53 per million inhabitants per annum. Genetic analysis of the codon 129 methionine/valine (M/V) polymorphism in all patients with sporadic CJD (sCJD) showed a trend for under-representation of VV cases (7.0%), compared with sCJD cohorts in other Western countries, whereas the MV genotype was relatively over-represented (22,4%). Combined PrP(Sc) and histopathological typing identified all sCJD subtypes known to date, except for the VV1 subtype. In particular, a "pure" phenotype was demonstrated in 60.1% of patients, whereas a mixed phenotype was detected in 39.9% of all sCJD cases. The relative excess of MV cases was largely accounted for by a relatively high incidence of the MV 2K subtype. Genetic analysis of the prion protein gene (PRNP) was performed in 161 patients and showed a mutation in 9 of them (5.6%), including one FFI and four GSS cases. Iatrogenic CJD was a rare phenomenon (3.1%), mainly associated with dura mater grafts. Three patients were diagnosed with new variant CJD (1.9%) and one with variably protease-sensitive prionopathy (VPSPr). Post-mortem examination revealed an alternative diagnosis in 156 patients, most commonly Alzheimer's disease (21.2%) or vascular causes of dementia (19.9%). The mortality rates of sCJD in the Netherlands are similar to those in other European countries, whereas iatrogenic and genetic cases are relatively rare. The unusual incidence of the VV2 sCJD subtype compared to that reported to date in other Western countries deserves further investigation.