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1.  Investigating the Genetics of Hippocampal Volume in Older Adults without Dementia 
PLoS ONE  2015;10(1):e0116920.
Hippocampal atrophy is observed with ageing and age-related neurodegenerative disease. Identification of the genetic correlates of hippocampal volume (HV) and atrophy may assist in elucidating the mechanisms of ageing and age-related neurodegeneration. Using two community cohorts of older Caucasians we estimated the heritability of HV and examined associations of HV with previously identified single nucleotide polymorphisms (SNPs). In addition we undertook genome-association studies (GWAS) examining HV and HV atrophy. Participants were community-dwelling non-demented older adults from the longitudinal Sydney Memory and Ageing Study (Sydney MAS) (N = 498) and the Older Australian Twins Study (OATS) (N = 351) aged 65 and over. HV was measured using T1-weighted magnetic resonance images. Heritability of HV was estimated in OATS. Genome-wide genotyping was imputed using the 1K Genomes reference set. Associations with HV-candidate and Alzheimer’s disease (AD)-related SNPs were investigated. A GWAS examining HV (in both cohorts) and an exploratory GWAS of HV atrophy over two years (in Sydney MAS only) were also undertaken. HV heritability was estimated at 62–65%. The previously identified GWAS HV SNP (rs6581612) and the candidate BDNF SNP (rs6265) were nominally significant (p = 0.047 and p = 0.041 respectively). No AD-related SNPs, including the APOE ε4 polymorphism, were significant. No significant results were observed for either of the GWAS undertaken. Despite our estimate of a high heritability of HV, our results are consistent with a highly polygenic model suggesting that SNPs identified from prior studies, including GWAS meta-analyses, can be difficult to replicate in smaller samples of older adults.
PMCID: PMC4308067  PMID: 25625606
2.  Symptom onset in autosomal dominant Alzheimer disease 
Neurology  2014;83(3):253-260.
To identify factors influencing age at symptom onset and disease course in autosomal dominant Alzheimer disease (ADAD), and develop evidence-based criteria for predicting symptom onset in ADAD.
We have collected individual-level data on ages at symptom onset and death from 387 ADAD pedigrees, compiled from 137 peer-reviewed publications, the Dominantly Inherited Alzheimer Network (DIAN) database, and 2 large kindreds of Colombian (PSEN1 E280A) and Volga German (PSEN2 N141I) ancestry. Our combined dataset includes 3,275 individuals, of whom 1,307 were affected by ADAD with known age at symptom onset. We assessed the relative contributions of several factors in influencing age at onset, including parental age at onset, age at onset by mutation type and family, and APOE genotype and sex. We additionally performed survival analysis using data on symptom onset collected from 183 ADAD mutation carriers followed longitudinally in the DIAN Study.
We report summary statistics on age at onset and disease course for 174 ADAD mutations, and discover strong and highly significant (p < 10−16, r2 > 0.38) correlations between individual age at symptom onset and predicted values based on parental age at onset and mean ages at onset by mutation type and family, which persist after controlling for APOE genotype and sex.
Significant proportions of the observed variance in age at symptom onset in ADAD can be explained by family history and mutation type, providing empirical support for use of these data to estimate onset in clinical research.
PMCID: PMC4117367  PMID: 24928124
3.  Genetics of Microstructure of the Corpus Callosum in Older Adults 
PLoS ONE  2014;9(12):e113181.
The current study sought to examine the relative influence of genetic and environmental factors on corpus callosum (CC) microstructure in a community sample of older adult twins. Analyses were undertaken in 284 healthy older twins (66% female; 79 MZ and 63 DZ pairs) from the Older Australian Twins Study. The average age of the sample was 69.82 (SD = 4.76) years. Brain imaging scans were collected and DTI measures were estimated for the whole CC as well as its five subregions. Parcellation of the CC was performed using Analyze. In addition, white matter lesion (WMLs) burden was estimated. Heritability and genetic correlation analyses were undertaken using the SOLAR software package. Age, sex, scanner, handedness and blood pressure were considered as covariates. Heritability (h2) analysis for the DTI metrics of whole CC, indicated significant h2 for fractional anisotropy (FA) (h2 = 0.56; p = 2.89×10−10), mean diffusivity (MD) (h2 = 0.52; p = 0.30×10−6), radial diffusivity (RD) (h2 = 0.49; p = 0.2×10−6) and axial diffusivity (AD) (h2 = 0.37; p = 8.15×10−5). We also performed bivariate genetic correlation analyses between (i) whole CC DTI measures and (ii) whole CC DTI measures with total brain WML burden. Across the DTI measures for the whole CC, MD and RD shared 84% of the common genetic variance, followed by MD- AD (77%), FA - RD (52%), RD - AD (37%) and FA – MD (11%). For total WMLs, significant genetic correlations indicated that there was 19% shared common genetic variance with whole CC MD, followed by CC RD (17%), CC AD (16%) and CC FA (5%). Our findings suggest that the CC microstructure is under moderate genetic control. There was also evidence of shared genetic factors between the CC DTI measures. In contrast, there was less shared genetic variance between WMLs and the CC DTI metrics, suggesting fewer common genetic variants.
PMCID: PMC4267776  PMID: 25514436
4.  Functional Connectivity in Autosomal Dominant and Late-Onset Alzheimer Disease 
JAMA neurology  2014;71(9):1111-1122.
Autosomal dominant Alzheimer disease (ADAD) is caused by rare genetic mutations in three specific genes, in contrast to late-onset Alzheimer Disease (LOAD), which has a more polygenetic risk profile.
Design, Setting, and Participants
We analyzed functional connectivity in multiple brain resting state networks (RSNs) in a cross-sectional cohort of ADAD (N=79) and LOAD (N=444) human participants using resting state functional connectivity MRI (rs-fcMRI) at multiple international academic sites.
Main Outcomes and Measures
For both types of AD, we quantified and compared functional connectivity changes in RSNs as a function of dementia severity as measured by clinical dementia rating (CDR). In ADAD, we qualitatively investigated functional connectivity changes with respect to estimated years from onset of symptoms within five RSNs.
Functional connectivity decreases with increasing CDR were similar for both LOAD and ADAD in multiple RSNs. Ordinal logistic regression models constructed in each type of AD accurately predicted CDR stage in the other, further demonstrating similarity of functional connectivity loss in each disease type. Among ADAD participants, functional connectivity in multiple RSNs appeared qualitatively lower in asymptomatic mutation carriers near their anticipated age of symptom onset compared to asymptomatic mutation non-carriers.
Conclusions and Relevance
rs-fcMRI changes with progressing AD severity are similar between ADAD and LOAD. Rs-fcMRI may be a useful endpoint for LOAD and ADAD therapy trials. ADAD disease process may be an effective model for LOAD disease process.
PMCID: PMC4240274  PMID: 25069482
Resting-state functional connectivity; autosomal dominant Alzheimer's disease; late-onset Alzheimer's disease; default mode network; apolipoprotein E (APOE)
5.  The Brain-Derived Neurotrophic Factor Val66Met Polymorphism Predicts Response to Exposure Therapy in Posttraumatic Stress Disorder 
Biological psychiatry  2013;73(11):1059-1063.
The most effective treatment for posttraumatic stress disorder (PTSD) is exposure therapy, which aims to facilitate extinction of conditioned fear. Recent evidence suggests that brain-derived neurotrophic factor (BDNF) facilitates extinction learning. This study assessed whether the Met-66 allele of BDNF, which results in lower activity-dependent secretion, predicts poor response to exposure therapy in PTSD.
Fifty-five patients with PTSD underwent an 8-week exposure-based cognitive behavior therapy program and provided mouth swabs or saliva to extract genomic DNA to determine their BDNF Val66Met genotype (30 patients with the Val/Val BDNF allele, 25 patients with the Met-66 allele). We examined whether BDNF genotype predicted reduction in PTSD severity following exposure therapy.
Analyses revealed poorer response to exposure therapy in the PTSD patients with the Met-66 allele of BDNF compared with patients with the Val/Val allele. Pretreatment Clinician Administered PTSD Scale severity and BDNF Val66Met polymorphism predicted response to exposure therapy using hierarchical regression.
This study provides the first evidence that the BDNF Val66Met genotype predicts response to cognitive behavior therapy in PTSD and is in accord with evidence that BDNF facilitates extinction learning.
PMCID: PMC4185184  PMID: 23312562
BDNF; CBT; fear extinction; fMRI; genetics; posttraumatic stress disorder; treatment predictor
6.  Variations in statin prescribing for primary cardiovascular disease prevention: cross-sectional analysis 
Statins are an important intervention for primary and secondary cardiovascular disease (CVD) prevention. We aimed to establish the variation in primary preventive treatment for CVD with statins in the English population.
Cross sectional analyses of 6155 English primary care practices with 40,017,963 patients in 2006/7. Linear regression was used to model prescribing rates of statins for primary CVD prevention as a function of IMD (index of multiple deprivation) quintile, proportion of population from an ethnic minority, and age over 65 years. Defined Daily Doses (DDD) were used to calculate the numbers of patients receiving a statin. Statin prescriptions were allocated to primary and secondary prevention based on the prevalence of CVD and stroke.
We estimated that 10.5% (s.d.3.7%) of the registered population were dispensed a statin for any indication and that 6.3% (s.d. 3.0%) received a statin for primary CVD prevention. The regression model explained 21.2% of the variation in estimates of prescribing for primary prevention. Practices with higher prevalence of hypertension (β co-efficient 0.299 p <0.001) and diabetes (β co-efficient 0.566 p < 0.001) prescribed more statins for primary prevention. Practices with higher levels of ethnicity (β co-efficient-0.026 p <0.001), greater deprivation (β co-efficient −0.152 p < 0.001) older patients (β co-efficient −0.032 p 0.002), larger lists (β co-efficient −0.085, p < 0.001) and were more rural (β co-efficient −0.121, p0.026) prescribed fewer statins. In a small proportion of practices (0.5%) estimated prescribing rates for statins were so low that insufficient prescriptions were issued to meet the predicted secondary prevention requirements of their registered population.
Absolute estimated prescribing rates for primary prevention of CVD were 6.3% of the population. There was evidence of social inequalities in statin prescribing for primary prevention. These findings support the recent introduction of a financial incentive for primary prevention of CVD in England.
Electronic supplementary material
The online version of this article (doi:10.1186/1472-6963-14-414) contains supplementary material, which is available to authorized users.
PMCID: PMC4263070  PMID: 25240604
Hydroxymethylglutaryl-CoA reductase inhibitors; Primary health care; Cardiovascular diseases
7.  Neuronal fiber bundle lengths in healthy adult carriers of the ApoE4 allele: A quantitative tractography DTI study 
Brain imaging and behavior  2013;7(3):10.1007/s11682-013-9225-4.
The epsilon 4 (e4) isoform of apolipoprotein E (ApoE) is a known genetic risk factor for suboptimal brain health. Morphometry studies of brains with Alzheimer’s disease have reported significant alterations in temporal lobe brain structure of e4 carriers, yet it remains unclear if the presence of an e4 allele is associated with alterations in the microstructure of white matter fiber bundles in healthy populations. The present study used quantitative tractography based on diffusion tensor imaging (qtDTI) to examine the influence of the e4 allele on temporal lobe fiber bundle lengths (FBLs) in 64 healthy older adults with at least one e4 allele (carriers, N=23) versus no e4 allele (non-carriers, N=41). Subtests from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were also analyzed to examine memory performance between groups. Analyses revealed shorter FBLs in the left uncinate fasciculus (UF) (p=.038) of e4 carriers compared to non-carriers. By contrast, neither FBLs specific to the temporal lobe nor memory performances differed significantly between groups. Increased age correlated significantly with shorter FBL in the temporal lobe and UF, and with decreased performance on tests of memory. This is the first study to utilize qtDTI to examine relationships between FBL and ApoE genotype. Results suggest that FBL in the UF is influenced by the presence of an ApoE e4 allele (ApoE4) in healthy older adults. Temporal lobe FBLs, however, are more vulnerable to aging than the presence of an e4 allele.
PMCID: PMC3726531  PMID: 23475756
ApoE; ApoE4; Tractography; DTI; White matter; Fiber bundle lengths; Aging
8.  Patterns of physical co-/multi-morbidity among patients with serious mental illness: a London borough-based cross-sectional study 
BMC Family Practice  2014;15:117.
Serious mental illness (SMI) is associated with elevated mortality compared to the general population; the majority of this excess is attributable to co-occurring common physical health conditions. There may be variation within the SMI group in the distribution of physical co/multi-morbidity. This study aims to a) compare the pattern of physical co- and multi-morbidity between patients with and without SMI within a South London primary care population; and, b) to explore socio-demographic and health risk factors associated with excess physical morbidity among the SMI group.
Data were obtained from Lambeth DataNet, a database of electronic patient records derived from general practices in the London borough of Lambeth. The pattern of 12 co-morbid common physical conditions was compared by SMI status. Multivariate ordinal and logistic regression analyses were conducted to assess the strength of association between each condition and SMI status; adjustments were made for potentially confounding socio-demographic characteristics and for potentially mediating health risk factors.
While SMI patients were more frequently recorded with all 12 physical conditions than non-SMI patients, the pattern of co-/multi-morbidity was similar between the two groups. Adjustment for socio-demographic characteristics – in particular age and, to a lesser extent ethnicity, considerably reduced effect sizes and accounted for some of the associations, though several conditions remained strongly associated with SMI status. Evidence for mediation by health risk factors, in particular BMI, was supported.
SMI patients are at an elevated risk of a range of physical health conditions than non-SMI patients but they do not appear to experience a different pattern of co-/multimorbidity among those conditions considered. Socio-demographic differences between the two groups account for some of the excess in morbidity and known health risk factors are likely to mediate the association. Further work to examine a wider range of conditions and health risk factors would help determine the extent of excess mortality attributable to these factors.
PMCID: PMC4062514  PMID: 24919453
Serious mental illness; Mental health; Physical health; Comorbidity; Multimorbidity
9.  Thyroid Antibodies, Autoimmunity and Cognitive Decline: Is There a Population-Based Link? 
Autoimmunity is considered an uncommon but under-recognised cause of cognitive decline.
Serum samples from 3,253 randomly selected subjects enrolled in the Hunter Community Study, aged 55-85 years, were assayed for thyrotropin stimulatory hormone, anti-thyroid peroxidase antibodies (TPO-Ab), anti-nuclear antibodies (ANA) and extractable nuclear antigens (ENA). Cognitive function was assessed using the Audio Recorded Cognitive Screen (ARCS) tool.
TPO-Ab were found in 8.4% and ANA in 27.9% of the study population, of whom 3% had positive ENA findings. No relationship was found between the ARCS score and either TPO-Ab (coefficient = 0.133; 95% CI −0.20, 0.82, p = 0.616), ANA at a low (coefficient = 1.01; 95% CI −2.58, 0.55, p = 0.203) or a high titre (coefficient = −0.65; 95% CI −2.59, 1.28, p = 0.508), or ENA antibodies (coefficient = 5.12; 95% CI −0.53, 10.77; p = 0.076).
Autoantibody findings are common in an aging population and are not associated with cognitive decline.
PMCID: PMC4067731  PMID: 24987403
Dementia; Hashimoto disease; Encephalitis; Autoantibodies; Anti-nuclear antibodies; Nuclear antigens; Autoimmune thyroiditis; Mild cognitive impairment
10.  Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification 
Neurogenetics  2013;14(1):11-22.
Familial idiopathic basal ganglia calcification (IBGC) or Fahr’s disease is a rare neurodegenerative disorder characterized by calcium deposits in the basal ganglia and other brain regions, which is associated with neuropsychiatric and motor symptoms. Familial IBGC is genetically heterogeneous and typically transmitted in an autosomal dominant fashion. We performed a mutational analysis of SLC20A2, the first gene found to cause IBGC, to assess its genetic contribution to familial IBGC. We recruited 218 subjects from 29 IBGC-affected families of varied ancestry and collected medical history, neurological exam, and head CT scans to characterize each patient’s disease status. We screened our patient cohort for mutations in SLC20A2. Twelve novel (nonsense, deletions, missense, and splice site) potentially pathogenic variants, one synonymous variant, and one previously reported mutation were identified in 13 families. Variants predicted to be deleterious cosegregated with disease in five families. Three families showed nonsegregation with clinical disease of such variants, but retrospective review of clinical and neuroimaging data strongly suggested previous misclassification. Overall, mutations in SLC20A2 account for as many as 41 % of our familial IBGC cases. Our screen in a large series expands the catalog of SLC20A2 mutations identified to date and demonstrates that mutations in SLC20A2 are a major cause of familial IBGC. Non-perfect segregation patterns of predicted deleterious variants highlight the challenges of phenotypic assessment in this condition with highly variable clinical presentation.
PMCID: PMC4023541  PMID: 23334463
Basal ganglia calcification; Fahr’s; Genetics; Sequencing; Mutations
11.  The Public Health Impact score: a new measure of public health effectiveness for general practices in England 
The British Journal of General Practice  2013;63(609):e291-e299.
Health policy in the UK is increasingly focused on the measurement of outcomes rather than structures and processes of health care.
To develop a measure of the effectiveness of primary care in terms of population health outcomes.
Design and setting
A cross-sectional study of general practices in England.
Twenty clinical quality of care indicators for which there was evidence of mortality reduction were identified from the national Quality and Outcomes Framework (QOF) pay-for-performance scheme. The number of lives saved by 8136 English practices (97.97% of all practices) in 2009/2010 was estimated, based on their performance on these measures, and a public health impact measure, the PHI score, was constructed. Multilevel regression models were used to identify practice and population predictors of PHI scores.
The mean estimated PHI score was 258.9 (standard deviation [SD] = 73.3) lives saved per 100 000 registered patients, per annum. This represents 75.7% of the maximum potential PHI score of 340.9 (SD = 91.8). PHI and QOF scores were weakly correlated (Pearson r = 0.28). The most powerful predictors of PHI score were the prevalence of the relevant clinical conditions (β = 0.77) and the proportion of patients aged ≥65 years (β = 0.22). General practices that were less successful at achieving their maximum potential PHI score were those with a lower prevalence of relevant conditions (β = 0.29), larger list sizes (β = −0.16), greater area deprivation (β = −0.15), and a larger proportion of patients aged ≥65 years (β = −0.13).
The PHI score is a potential alternative metric of practice performance, measuring the estimated mortality reduction in the registered population. Rewards under the QOF pay-for-performance scheme are not closely aligned to the public health impact of practices.
PMCID: PMC3609477  PMID: 23540486
health outcomes; population mortality reduction; primary health care
12.  Characterisation of Genetic Variation in ST8SIA2 and Its Interaction Region in NCAM1 in Patients with Bipolar Disorder 
PLoS ONE  2014;9(3):e92556.
Alpha-2,8-sialyltransferase 2 (ST8SIA2) is an enzyme responsible for the transfer of polysialic acid (PSA) to glycoproteins, principally the neuronal cell adhesion molecule (NCAM1), and is involved in neuronal plasticity. Variants within ST8SIA2 have previously shown association with bipolar disorder, schizophrenia and autism. In addition, altered PSA-NCAM expression in brains of patients with schizophrenia or bipolar disorder indicates a functional dysregulation of glycosylation in mental illness. To explore the role of sequence variation affecting PSA-NCAM formation, we conducted a targeted re-sequencing study of a ∼100 kb region – including the entire ST8SIA2 gene and its region of interaction with NCAM1 – in 48 Caucasian cases with bipolar disorder using the Roche 454 platform. We identified over 400 DNA variants, including 47 putative novel variants not described in dbSNP. Validation of a subset of variants via Sequenom showed high reliability of Roche 454 genotype calls (97% genotype concordance, with 80% of novel variants independently verified). We did not observe major loss-of-function mutations that would affect PSA-NCAM formation, either by ablating ST8SIA2 function or by affecting the ability of NCAM1 to be glycosylated. However, we identified 13 SNPs in the UTRs of ST8SIA2, a synonymous coding SNP in exon 5 (rs2305561, P207P) and many additional non-coding variants that may influence splicing or regulation of ST8SIA2 expression. We calculated nucleotide diversity within ST8SIA2 on specific haplotypes, finding that the diversity on the specific “risk” and “protective” haplotypes was lower than other non-disease-associated haplotypes, suggesting that putative functional variation may have arisen on a spectrum of haplotypes. We have identified common and novel variants (rs11074064, rs722645, 15∶92961050) that exist on a spectrum of haplotypes, yet are plausible candidates for conferring the effect of risk and protective haplotypes via multiple enhancer elements. A Galaxy workflow/pipeline for sequence analysis used herein is available at:
PMCID: PMC3961385  PMID: 24651862
13.  Bilingualism Does Not Alter Cognitive Decline or Dementia Risk among Spanish-Speaking Immigrants 
Neuropsychology  2013;28(2):238-246.
Clinic-based studies suggest that dementia is diagnosed at older ages in bilinguals compared to monolinguals. The current study sought to test this hypothesis in a large, prospective, community-based study of initially non-demented Hispanic immigrants living in a Spanish-speaking enclave of Northern Manhattan.
Participants included 1,067 participants in the Washington/Hamilton Heights Inwood Columbia Aging Project (WHICAP) who were tested in Spanish and followed at 18–24 month intervals for up to 23 years. Spanish-English bilingualism was estimated via both self-report and an objective measure of English reading level. Multilevel models for change estimated the independent effects of bilingualism on cognitive decline in four domains: episodic memory, language, executive function, and speed. Over the course of the study, 282 participants developed dementia. Cox regression was used to estimate the independent effect of bilingualism on dementia conversion. Covariates included country of origin, gender, education, time spent in the United States, recruitment cohort, and age at enrollment.
Independent of the covariates, bilingualism was associated with better memory and executive function at baseline. However bilingualism was not independently associated with rates of cognitive decline or dementia conversion. Results were similar whether bilingualism was measured via self-report or an objective test of reading level.
This study does not support a protective effect of bilingualism on age-related cognitive decline or the development of dementia. In this sample of Hispanic immigrants, bilingualism is related to higher initial scores on cognitive tests and higher educational attainment and may not represent a unique source of cognitive reserve.
PMCID: PMC3947427  PMID: 24188113
Cognitive aging; episodic memory; executive function; language; statistical modeling
14.  Impaired default network functional connectivity in autosomal dominant Alzheimer disease 
Neurology  2013;81(8):736-744.
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.
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).
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.
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.
PMCID: PMC3776464  PMID: 23884042
15.  Traumatic Brain Injury and Olfaction: A Systematic Review 
Traumatic brain injury (TBI) is a common condition that is often complicated by neuropsychiatric sequelae that can have major impacts on function and quality of life. An alteration in the sense of smell is recognized as a relatively common complication of TBI; however in clinical practice, this complication may not be sought or adequately characterized. We conducted a systematic review of studies concerned with olfactory functioning following TBI. Our predetermined criteria led to the identification of 25 studies published in English, which we examined in detail. We have tabulated the data from these studies in eight separate tables, beginning with Table 1, which highlights each study’s key findings, and we provide a summary/synthesis of the findings in the accompanying results and discussion sections. Despite widely differing methodologies, the studies attest to a high frequency of post-TBI olfactory dysfunction and indicate that its presence can serve as a potential marker of additional structural or functional morbidities.
PMCID: PMC3897870  PMID: 24478752
brain injury; olfaction; anosmia; trauma; review
16.  The ENIGMA Consortium: large-scale collaborative analyses of neuroimaging and genetic data 
Thompson, Paul M. | Stein, Jason L. | Medland, Sarah E. | Hibar, Derrek P. | Vasquez, Alejandro Arias | Renteria, Miguel E. | Toro, Roberto | Jahanshad, Neda | Schumann, Gunter | Franke, Barbara | Wright, Margaret J. | Martin, Nicholas G. | Agartz, Ingrid | Alda, Martin | Alhusaini, Saud | Almasy, Laura | Almeida, Jorge | Alpert, Kathryn | Andreasen, Nancy C. | Andreassen, Ole A. | Apostolova, Liana G. | Appel, Katja | Armstrong, Nicola J. | Aribisala, Benjamin | Bastin, Mark E. | Bauer, Michael | Bearden, Carrie E. | Bergmann, Ørjan | Binder, Elisabeth B. | Blangero, John | Bockholt, Henry J. | Bøen, Erlend | Bois, Catherine | Boomsma, Dorret I. | Booth, Tom | Bowman, Ian J. | Bralten, Janita | Brouwer, Rachel M. | Brunner, Han G. | Brohawn, David G. | Buckner, Randy L. | Buitelaar, Jan | Bulayeva, Kazima | Bustillo, Juan R. | Calhoun, Vince D. | Cannon, Dara M. | Cantor, Rita M. | Carless, Melanie A. | Caseras, Xavier | Cavalleri, Gianpiero L. | Chakravarty, M. Mallar | Chang, Kiki D. | Ching, Christopher R. K. | Christoforou, Andrea | Cichon, Sven | Clark, Vincent P. | Conrod, Patricia | Coppola, Giovanni | Crespo-Facorro, Benedicto | Curran, Joanne E. | Czisch, Michael | Deary, Ian J. | de Geus, Eco J. C. | den Braber, Anouk | Delvecchio, Giuseppe | Depondt, Chantal | de Haan, Lieuwe | de Zubicaray, Greig I. | Dima, Danai | Dimitrova, Rali | Djurovic, Srdjan | Dong, Hongwei | Donohoe, Gary | Duggirala, Ravindranath | Dyer, Thomas D. | Ehrlich, Stefan | Ekman, Carl Johan | Elvsåshagen, Torbjørn | Emsell, Louise | Erk, Susanne | Espeseth, Thomas | Fagerness, Jesen | Fears, Scott | Fedko, Iryna | Fernández, Guillén | Fisher, Simon E. | Foroud, Tatiana | Fox, Peter T. | Francks, Clyde | Frangou, Sophia | Frey, Eva Maria | Frodl, Thomas | Frouin, Vincent | Garavan, Hugh | Giddaluru, Sudheer | Glahn, David C. | Godlewska, Beata | Goldstein, Rita Z. | Gollub, Randy L. | Grabe, Hans J. | Grimm, Oliver | Gruber, Oliver | Guadalupe, Tulio | Gur, Raquel E. | Gur, Ruben C. | Göring, Harald H. H. | Hagenaars, Saskia | Hajek, Tomas | Hall, Geoffrey B. | Hall, Jeremy | Hardy, John | Hartman, Catharina A. | Hass, Johanna | Hatton, Sean N. | Haukvik, Unn K. | Hegenscheid, Katrin | Heinz, Andreas | Hickie, Ian B. | Ho, Beng-Choon | Hoehn, David | Hoekstra, Pieter J. | Hollinshead, Marisa | Holmes, Avram J. | Homuth, Georg | Hoogman, Martine | Hong, L. Elliot | Hosten, Norbert | Hottenga, Jouke-Jan | Hulshoff Pol, Hilleke E. | Hwang, Kristy S. | Jack, Clifford R. | Jenkinson, Mark | Johnston, Caroline | Jönsson, Erik G. | Kahn, René S. | Kasperaviciute, Dalia | Kelly, Sinead | Kim, Sungeun | Kochunov, Peter | Koenders, Laura | Krämer, Bernd | Kwok, John B. J. | Lagopoulos, Jim | Laje, Gonzalo | Landen, Mikael | Landman, Bennett A. | Lauriello, John | Lawrie, Stephen M. | Lee, Phil H. | Le Hellard, Stephanie | Lemaître, Herve | Leonardo, Cassandra D. | Li, Chiang-shan | Liberg, Benny | Liewald, David C. | Liu, Xinmin | Lopez, Lorna M. | Loth, Eva | Lourdusamy, Anbarasu | Luciano, Michelle | Macciardi, Fabio | Machielsen, Marise W. J. | MacQueen, Glenda M. | Malt, Ulrik F. | Mandl, René | Manoach, Dara S. | Martinot, Jean-Luc | Matarin, Mar | Mather, Karen A. | Mattheisen, Manuel | Mattingsdal, Morten | Meyer-Lindenberg, Andreas | McDonald, Colm | McIntosh, Andrew M. | McMahon, Francis J. | McMahon, Katie L. | Meisenzahl, Eva | Melle, Ingrid | Milaneschi, Yuri | Mohnke, Sebastian | Montgomery, Grant W. | Morris, Derek W. | Moses, Eric K. | Mueller, Bryon A. | Muñoz Maniega, Susana | Mühleisen, Thomas W. | Müller-Myhsok, Bertram | Mwangi, Benson | Nauck, Matthias | Nho, Kwangsik | Nichols, Thomas E. | Nilsson, Lars-Göran | Nugent, Allison C. | Nyberg, Lars | Olvera, Rene L. | Oosterlaan, Jaap | Ophoff, Roel A. | Pandolfo, Massimo | Papalampropoulou-Tsiridou, Melina | Papmeyer, Martina | Paus, Tomas | Pausova, Zdenka | Pearlson, Godfrey D. | Penninx, Brenda W. | Peterson, Charles P. | Pfennig, Andrea | Phillips, Mary | Pike, G. Bruce | Poline, Jean-Baptiste | Potkin, Steven G. | Pütz, Benno | Ramasamy, Adaikalavan | Rasmussen, Jerod | Rietschel, Marcella | Rijpkema, Mark | Risacher, Shannon L. | Roffman, Joshua L. | Roiz-Santiañez, Roberto | Romanczuk-Seiferth, Nina | Rose, Emma J. | Royle, Natalie A. | Rujescu, Dan | Ryten, Mina | Sachdev, Perminder S. | Salami, Alireza | Satterthwaite, Theodore D. | Savitz, Jonathan | Saykin, Andrew J. | Scanlon, Cathy | Schmaal, Lianne | Schnack, Hugo G. | Schork, Andrew J. | Schulz, S. Charles | Schür, Remmelt | Seidman, Larry | Shen, Li | Shoemaker, Jody M. | Simmons, Andrew | Sisodiya, Sanjay M. | Smith, Colin | Smoller, Jordan W. | Soares, Jair C. | Sponheim, Scott R. | Sprooten, Emma | Starr, John M. | Steen, Vidar M. | Strakowski, Stephen | Strike, Lachlan | Sussmann, Jessika | Sämann, Philipp G. | Teumer, Alexander | Toga, Arthur W. | Tordesillas-Gutierrez, Diana | Trabzuni, Daniah | Trost, Sarah | Turner, Jessica | Van den Heuvel, Martijn | van der Wee, Nic J. | van Eijk, Kristel | van Erp, Theo G. M. | van Haren, Neeltje E. M. | van ‘t Ent, Dennis | van Tol, Marie-Jose | Valdés Hernández, Maria C. | Veltman, Dick J. | Versace, Amelia | Völzke, Henry | Walker, Robert | Walter, Henrik | Wang, Lei | Wardlaw, Joanna M. | Weale, Michael E. | Weiner, Michael W. | Wen, Wei | Westlye, Lars T. | Whalley, Heather C. | Whelan, Christopher D. | White, Tonya | Winkler, Anderson M. | Wittfeld, Katharina | Woldehawariat, Girma | Wolf, Christiane | Zilles, David | Zwiers, Marcel P. | Thalamuthu, Anbupalam | Schofield, Peter R. | Freimer, Nelson B. | Lawrence, Natalia S. | Drevets, Wayne
Brain Imaging and Behavior  2014;8(2):153-182.
The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA’s first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.
PMCID: PMC4008818  PMID: 24399358
Genetics; MRI; GWAS; Consortium; Meta-analysis; Multi-site
17.  Common Variant at 16p11.2 Conferring Risk of Psychosis 
Steinberg, Stacy | de Jong, Simone | Mattheisen, Manuel | Costas, Javier | Demontis, Ditte | Jamain, Stéphane | Pietiläinen, Olli P H | Lin, Kuang | Papiol, Sergi | Huttenlocher, Johanna | Sigurdsson, Engilbert | Vassos, Evangelos | Giegling, Ina | Breuer, René | Fraser, Gillian | Walker, Nicholas | Melle, Ingrid | Djurovic, Srdjan | Agartz, Ingrid | Tuulio-Henriksson, Annamari | Suvisaari, Jaana | Lönnqvist, Jouko | Paunio, Tiina | Olsen, Line | Hansen, Thomas | Ingason, Andres | Pirinen, Matti | Strengman, Eric | Hougaard, David M | Ørntoft, Torben | Didriksen, Michael | Hollegaard, Mads V | Nordentoft, Merete | Abramova, Lilia | Kaleda, Vasily | Arrojo, Manuel | Sanjuán, Julio | Arango, Celso | Etain, Bruno | Bellivier, Frank | Méary, Alexandre | Schürhoff, Franck | Szoke, Andrei | Ribolsi, Michele | Magni, Valentina | Siracusano, Alberto | Sperling, Swetlana | Rossner, Moritz | Christiansen, Claus | Kiemeney, Lambertus A | Franke, Barbara | van den Berg, Leonard H | Veldink, Jan | Curran, Sarah | Bolton, Patrick | Poot, Martin | Staal, Wouter | Rehnstrom, Karola | Kilpinen, Helena | Freitag, Christine M | Meyer, Jobst | Magnusson, Pall | Saemundsen, Evald | Martsenkovsky, Igor | Bikshaieva, Iana | Martsenkovska, Inna | Vashchenko, Olesya | Raleva, Marija | Paketchieva, Kamka | Stefanovski, Branislav | Durmishi, Naser | Milovancevic, Milica Pejovic | Tosevski, Dusica Lecic | Silagadze, Teimuraz | Naneishvili, Nino | Mikeladze, Nina | Surguladze, Simon | Vincent, John B | Farmer, Anne | Mitchell, Philip B | Wright, Adam | Schofield, Peter R | Fullerton, Janice M | Montgomery, Grant W | Martin, Nicholas G | Rubino, I Alex | van Winkel, Ruud | Kenis, Gunter | De Hert, Marc | Réthelyi, János M | Bitter, István | Terenius, Lars | Jönsson, Erik G | Bakker, Steven | van Os, Jim | Jablensky, Assen | Leboyer, Marion | Bramon, Elvira | Powell, John | Murray, Robin | Corvin, Aiden | Gill, Michael | Morris, Derek | O’Neill, F Anthony | Kendler, Ken | Riley, Brien | Craddock, Nick | Owen, Michael J | O’Donovan, Michael C | Thorsteinsdottir, Unnur | Kong, Augustine | Ehrenreich, Hannelore | Carracedo, Angel | Golimbet, Vera | Andreassen, Ole A | Børglum, Anders D | Mors, Ole | Mortensen, Preben B | Werge, Thomas | Ophoff, Roel A | Nöthen, Markus M | Rietschel, Marcella | Cichon, Sven | Ruggeri, Mirella | Tosato, Sarah | Palotie, Aarno | St Clair, David | Rujescu, Dan | Collier, David A | Stefansson, Hreinn | Stefansson, Kari
Molecular psychiatry  2012;19(1):10.1038/mp.2012.157.
Epidemiological and genetic data support the notion that schizophrenia and bipolar disorder share genetic risk factors. In our previous genome-wide association (GWA) study, meta-analysis and follow-up (totaling as many as 18,206 cases and 42,536 controls), we identified four loci showing genome-wide significant association with schizophrenia. Here we consider a mixed schizophrenia and bipolar disorder (psychosis) phenotype (addition of 7,469 bipolar disorder cases, 1,535 schizophrenia cases, 333 other psychosis cases, 808 unaffected family members and 46,160 controls). Combined analysis reveals a novel variant at 16p11.2 showing genome-wide significant association (rs4583255[T], OR = 1.08, P = 6.6 × 10−11). The new variant is located within a 593 kb region that substantially increases risk of psychosis when duplicated. In line with the association of the duplication with reduced body mass index (BMI), rs4583255[T] is also associated with lower BMI (P = 0.0039 in the public GIANT consortium dataset; P = 0.00047 in 22,651 additional Icelanders).
PMCID: PMC3872086  PMID: 23164818
schizophrenia; bipolar disorder; association; 16p11.2; cross-disorder
18.  Achievement of cholesterol targets and prescribing of higher-cost statins: a cross-sectional study in general practice 
The British Journal of General Practice  2012;62(605):e815-e820.
There is conflicting evidence as to whether achievement of cholesterol targets at the population level is dependent on the choice and cost of statin.
To investigate the practice-level relationship between cholesterol quality indicators in patients with heart disease, stroke, and diabetes and prescribing of low-cost statins.
Design and setting
Correlations and linear regression modelling of retrospective cross-sectional practice-level data with potential explanatory variables in 7909 (96.4%) general practices in England in 2008–2009.
Quality indicator data were obtained from the Information Centre and prescribing data from the NHS Business Authority. A ‘cholesterol quality indicator’ score was constructed by dividing the numbers of patients achieving the target for cholesterol control of ≤5 mmol/l in stroke, diabetes, and heart disease by the numbers on each register. A ‘low-cost statin’ ratio score was constructed by dividing the numbers of defined daily doses of simvastatin and pravastatin by the total numbers of defined daily doses of statins.
Simvastatin accounted for 83.3% (standard deviation [SD] = 15.7%) of low-cost statins prescribed and atorvastatin accounted for 85.7% (SD = 14.8%) of high-cost statins prescribed. The mean cholesterol score was 73.7% (SD = 6.0%). Practices using a higher proportion of the low-cost statins were less successful in achieving cholesterol targets. An increase of 10% in the prescribing of low-cost statins was associated with a decrease of 0.46% in the cholesterol quality indicator score (95% confidence interval = –0.54% to –0.38%, P<0.001).
Greater use of low-cost statins was associated with a small reduction in cholesterol control.
PMCID: PMC3505414  PMID: 23211261
costs and cost analysis; hydroxymethylglutaryl-CoA reductase inhibitors; primary health care
19.  Cluster randomized controlled trial of a psycho-educational intervention for people with a family history of depression for use in general practice 
BMC Psychiatry  2013;13:325.
The strongest risk factor for depression is having a family history of the condition. Many individuals with a family history of depression are concerned about their personal risk for depression and report unmet educational and psychological support needs. No supportive and/or educational interventions are currently available that target this group of individuals. In this study we will develop and evaluate the first online psycho-educational intervention targeted to individuals with a family history of depression. Genetic risk information and evidence-rated information on preventive strategies for depression will be provided to such individuals in a general practice setting. The intervention will also incorporate a risk assessment tool. The content and delivery of the intervention will be pilot-tested.
The proposed intervention will be evaluated in the general practitioner (GPs) setting, using a cluster randomized controlled trial. GP practices will be randomized to provide either access to the online, targeted psycho-educational intervention or brief generic information about depression (control) to eligible patients. Eligibility criteria include having at least one first-degree relative with either major depressive disorder (MDD) or bipolar disorder (BD). The primary outcome measure is 'intention to adopt, or actual adoption of, risk-reducing strategies’. Secondary outcome measures include: depression symptoms, perceived stigma of depression, knowledge of risk factors for development of depression and risk-reducing strategies, and perceived risk of developing depression or having a recurrence of family history. Over the course of the study, participants will complete online questionnaires at three time points: at baseline, and two weeks and six months after receiving the intervention or control condition.
This novel psycho-educational intervention will provide individuals with a family history of depression with information on evidence-based strategies for the prevention of depression, thus, we hypothesize, enabling them to make appropriate lifestyle choices and implement behaviors designed to reduce their risk for depression. The online psycho-educational intervention will also provide a model for similar interventions aimed at individuals at increased familial risk for other psychiatric disorders.
Trial registration
The study is registered with the Australian and New Zealand Clinical Trials Group (Registration no: ACTRN12613000402741).
PMCID: PMC3897985  PMID: 24289740
Family history; Major depressive disorder; Bipolar disorder; Online intervention; Psycho-education; Prevention
20.  The pattern of atrophy in familial Alzheimer disease 
Neurology  2013;81(16):1425-1433.
To assess regional patterns of gray and white matter atrophy in familial Alzheimer disease (FAD) mutation carriers.
A total of 192 participants with volumetric T1-weighted MRI, genotyping, and clinical diagnosis were available from the Dominantly Inherited Alzheimer Network. Of these, 69 were presymptomatic mutation carriers, 50 were symptomatic carriers (31 with Clinical Dementia Rating [CDR] = 0.5, 19 with CDR > 0.5), and 73 were noncarriers from the same families. Voxel-based morphometry was used to identify cross-sectional group differences in gray matter and white matter volume.
Significant differences in gray matter (p < 0.05, family-wise error–corrected) were observed between noncarriers and mildly symptomatic (CDR = 0.5) carriers in the thalamus and putamen, as well as in the temporal lobe, precuneus, and cingulate gyrus; the same pattern, but with more extensive changes, was seen in those with CDR > 0.5. Significant white matter differences between noncarriers and symptomatic carriers were observed in the cingulum and fornix; these form input and output connections to the medial temporal lobe, cingulate, and precuneus. No differences between noncarriers and presymptomatic carriers survived correction for multiple comparisons, but there was a trend for decreased gray matter in the thalamus for carriers closer to their estimated age at onset. There were no significant increases of gray or white matter in asymptomatic or symptomatic carriers compared to noncarriers.
Atrophy in FAD is observed early, both in areas commonly associated with sporadic Alzheimer disease and also in the putamen and thalamus, 2 regions associated with early amyloid deposition in FAD mutation carriers.
PMCID: PMC3806583  PMID: 24049139
21.  Managing hypertension in general practice: a cross-sectional study of treatment and ethnicity 
The British Journal of General Practice  2012;62(603):e703-e709.
NICE guidelines are the accepted standard for determining the management of hypertension in UK primary care.
To explore adherence and non-adherence to NICE hypertension guidelines, the extent to which this influences blood pressure control, and the role of ethnicity.
Design and setting
A cross-sectional study was conducted based on primary care data from Lambeth DataNet, a database of primary care records in one inner-city London borough.
NICE guidelines were used to determine adherence to recommended treatment options for four groups of patients with hypertension: aged <55 years on monotherapy; aged ≥55 years on monotherapy; any age on dual therapy; any age and with comorbid diabetes. Blood pressure control was determined for each treatment category and ethnic group. The study controlled for age, sex, social deprivation, and clustering within general practices.
A total of 32 183 patients were identified with a current diagnosis of hypertension. Ethnic coding was available for 28 320 (88.0%). Overall, 13 546 patients with ethnicity coding could be allocated to one of the four clinical categories of hypertension; 44% of these patients received non-guideline-adherent treatment; ethnicity was not a significant determinant. Mean arterial pressure did not differ significantly between those receiving ‘correct’ or ‘incorrect’ hypotensive therapy.
Evidence-based guidelines for the management of hypertension were not followed in a relatively large proportion of patients included in this study. Nevertheless, no evidence was found that failure to follow treatment recommendations resulted in poorer blood pressure control. Further work is needed to determine the reasons for non-implementation of guideline recommendations in primary care.
PMCID: PMC3459778  PMID: 23265230
ethnicity; guidelines; hypertension; primary care
22.  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.
PMCID: PMC3489185  PMID: 23139856
Alzheimer disease; autosomal dominant; biomarkers of Alzheimer disease; PSEN1; PSEN2; APP; amyloid-beta; preclinical Alzheimer disease
23.  C9ORF72 repeat expansion in clinical and neuropathologic frontotemporal dementia cohorts 
Neurology  2012;79(10):995-1001.
To determine the frequency of a hexanucleotide repeat expansion in C9ORF72, a gene of unknown function implicated in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), in Australian FTD patient cohorts and to examine the clinical and neuropathologic phenotypes associated with this expansion.
We examined a clinically ascertained FTD cohort (n = 89) and a neuropathologically ascertained cohort of frontotemporal lobar degeneration cases with TDP-43 pathology (FTLD-TDP) (n = 22) for the C9ORF72 hexanucleotide repeat expansion using a repeat primed PCR assay. All expansion-positive patients were genotyped for rs3849942, a surrogate marker for the chromosome 9p21 risk haplotype previously associated with FTD and ALS.
The C9ORF72 repeat expansion was detected in 10% of patients in the clinically diagnosed cohort, rising to 29% in those with a positive family history of early-onset dementia or ALS. The prevalence of psychotic features was significantly higher in expansion-positive cases (56% vs 14%). In the pathology cohort, 41% of TDP-43-positive cases harbored the repeat expansion, and all exhibited type B pathology. One of the 17 expansion-positive probands was homozygous for the “nonrisk” G allele of rs3849942.
The C9ORF72 repeat expansion is a relatively common cause of FTD in Australian populations, and is especially common in those with FTD-ALS, psychotic features, and a strong family history. Detection of a repeat expansion on the 9p21 putative “nonrisk” haplotype suggests that not all mutation carriers are necessarily descended from a common founder and indicates that the expansion may have occurred on multiple haplotype backgrounds.
PMCID: PMC3430710  PMID: 22875086
24.  Endogenous progesterone levels and frontotemporal dementia: modulation of TDP-43 and Tau levels in vitro and treatment of the A315T TARDBP mouse model 
Disease Models & Mechanisms  2013;6(5):1198-1204.
Frontotemporal dementia (FTD) is associated with motor neurone disease (FTD-MND), corticobasal syndrome (CBS) and progressive supranuclear palsy syndrome (PSPS). Together, this group of disorders constitutes a major cause of young-onset dementia. One of the three clinical variants of FTD is progressive nonfluent aphasia (PNFA), which is focused on in this study. The steroid hormone progesterone (PROG) is known to have an important role as a neurosteroid with potent neuroprotective and promyelination properties. In a case-control study of serum samples (39 FTD, 91 controls), low serum PROG was associated with FTD overall. In subgroup analysis, low PROG levels were significantly associated with FTD-MND and CBS, but not with PSPS or PNFA. PROG levels of >195 pg/ml were significantly correlated with lower disease severity (frontotemporal dementia rating scale) for individuals with CBS. In the human neuroblastoma SK-N-MC cell line, exogenous PROG (9300–93,000 pg/ml) had a significant effect on overall Tau and nuclear TDP-43 levels, reducing total Tau levels by ∼1.5-fold and increasing nuclear TDP-43 by 1.7- to 2.0-fold. Finally, elevation of plasma PROG to a mean concentration of 5870 pg/ml in an Ala315Thr (A315T) TARDBP transgenic mouse model significantly reduced the rate of loss of locomotor control in PROG-treated, compared with placebo, mice. The PROG treatment did not significantly increase survival of the mice, which might be due to the limitation of the transgenic mouse to accurately model TDP-43-mediated neurodegeneration. Together, our clinical, cellular and animal data provide strong evidence that PROG could be a valid therapy for specific related disorders of FTD.
PMCID: PMC3759339  PMID: 23798570
25.  GSK3B and MAPT Polymorphisms Are Associated with Grey Matter and Intracranial Volume in Healthy Individuals 
PLoS ONE  2013;8(8):e71750.
The microtubule-associated protein tau gene (MAPT) codes for a protein that plays an integral role in stabilisation of microtubules and axonal transport in neurons. As well as its role in susceptibility to neurodegeneration, previous studies have found an association between the MAPT haplotype and intracranial volume and regional grey matter volumes in healthy adults. The glycogen synthase kinase-3β gene (GSK3B) codes for a serine/threonine kinase that phosphorylates various proteins, including tau, and has also been associated with risk for neurodegenerative disorders and schizophrenia. We examined the effects of MAPT and two functional promoter polymorphisms in GSK3B (rs3755557 and rs334558) on total grey matter and intracranial volume in three independent cohorts totaling 776 neurologically healthy individuals. In vitro analyses revealed a significant effect of rs3755557 on gene expression, and altered binding of at least two transcription factors, Octamer transcription factor 1 (Oct-1) and Pre-B-cell leukemia transcription factor 1 (Pbx-1), to the GSK3B promoter. Meta-analysis across the three cohorts revealed a significant effect of rs3755557 on total grey matter volume (summary B = 0.082, 95% confidence interval = 0.037–0.128) and intracranial volume (summary B = 0.113, 95% confidence interval = 0.082–0.144). No significant effect was observed for MAPT H1/H2 diplotype or GSK3B rs334558 on total grey matter or intracranial volume. Our genetic and biochemical analyses have identified a role for GSK3B in brain development, which could have important aetiological implications for neurodegenerative and neurodevelopmental disorders.
PMCID: PMC3741177  PMID: 23951236

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