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Linkage disequilibrium fine mapping and haplotype association analysis of the tau gene in progressive supranuclear palsy and corticobasal degeneration.

ABSTRACT: The haplotype H1 of the tau gene, MAPT, is highly associated with progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD).To investigate the pathogenic basis of this association.Detailed linkage disequilibrium and common haplotype structure of MAPT were examined in 27 CEPH trios using validated HapMap genotype data for 24 single nucleotide polymorphisms (SNPs) spanning MAPT.Multiple variants of the H1 haplotype were resolved, reflecting a far greater diversity of MAPT than can be explained by the H1 and H2 clades alone. Based on this, six haplotype tagging SNPs (htSNPs) that capture 95% of the common haplotype diversity were used to genotype well characterised PSP and CBD case-control cohorts. In addition to strong association with PSP and CBD of individual SNPs, two common haplotypes derived from these htSNPs were identified that are highly associated with PSP: the sole H2 derived haplotype was underrepresented and one of the common H1 derived haplotypes was highly associated, with a similar trend observed in CBD. There were powerful and highly significant associations with PSP and CBD of haplotypes formed by three H1 specific SNPs. This made it possible to define a candidate region of at least approximately 56 kb, spanning sequences from upstream of MAPT exon 1 to intron 9. On the H1 haplotype background, these could harbour the pathogenic variants.The findings support the pathological evidence that underlying variations in MAPT could contribute to disease pathogenesis by subtle effects on gene expression and/or splicing. They also form the basis for the investigation of the possible genetic role of MAPT in Parkinson's disease and other tauopathies, including Alzheimer's disease.

SUBMITTER: Pittman AM

PROVIDER: S-EPMC1735957 | biostudies-other | 2005 Nov

REPOSITORIES: biostudies-other

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Linkage disequilibrium fine mapping and haplotype association analysis of the tau gene in progressive supranuclear palsy and corticobasal degeneration.

Pittman A M AM Myers A J AJ Abou-Sleiman P P Fung H C HC Kaleem M M Marlowe L L Duckworth J J Leung D D Williams D D Kilford L L Thomas N N Morris C M CM Dickson D D Wood N W NW Hardy J J Lees A J AJ de Silva R R

Journal of medical genetics 20050325 11

<h4>Background</h4>The haplotype H1 of the tau gene, MAPT, is highly associated with progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD).<h4>Objective</h4>To investigate the pathogenic basis of this association.<h4>Methods</h4>Detailed linkage disequilibrium and common haplotype structure of MAPT were examined in 27 CEPH trios using validated HapMap genotype data for 24 single nucleotide polymorphisms (SNPs) spanning MAPT.<h4>Results</h4>Multiple variants of the H1 haplotype ...[more]

PMID: 15792962

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Project description:ImportanceWe provide novel evidence of specific clinical and neuroimaging features that may help for the in vivo prediction of underlying pathology in patients with nonfluent/agrammatic primary progressive aphasia (nfvPPA) and progressive supranuclear palsy (PSP) or corticobasal degeneration (CBD) proved by autopsy.ObjectiveTo characterize the neurological, cognitive, and neuroimaging features of patients with nfvPPA-in whom either PSP or CBD was eventually confirmed at autopsy-at initial presentation and at 1-year follow-up.Design, setting, and participantsA prospective longitudinal clinical-pathological study was conducted in a tertiary research clinic that specialized in cognitive disorders. Fourteen patients were evaluated between January 2002 and December 2014. Inclusion criteria for the study were a clinical diagnosis of nfvPPA; the availability of speech, language, and cognitive testing for at least 1 evaluation; magnetic resonance imaging within 6 months of initial evaluation; and a postmortem pathological diagnosis of PSP or CBD. Ten matched healthy control participants were also included.Main outcomes and measuresClinical, cognitive, and neuroimaging longitudinal data were analyzed to characterize the whole nfvPPA-4-repeat-tau group and identify differences between nfvPPA-PSP and nfvPPA-CBD both at presentation and longitudinally.ResultsPatient groups did not differ significantly in age, sex, or handedness (nfvPPA-PSP group: median [interquartile range (IQR)] age, 74 [67-76] years; 1 of 5 male [20%]; 1 of 5 left-handed [20%]; and nfvPPA-CBD group: mean [IQR] age, 65 [54-81] years; 3 of 9 male [33%]; 0 left-handed). Motor speech impairment and left frontal white matter atrophy were the most prominent common features. At presentation, dysarthria (Motor Speech Examination median [IQR] score: nfvPPA-PSP, 4 [2-7]; nfvPPA-CBD, 0 [0-4]; P = .02), depression (Geriatric Depression Scale median [IQR] score: nfvPPA-PSP, 19 [3-28]; nfvPPA-CBD, 4 [0-16]; P = .04), and relatively selective white matter atrophy were typical of the nfvPPA-PSP group, while greater gray matter atrophy and a trend toward greater sentence comprehension deficits (median [IQR] sentence comprehension correct: nfvPPA-PSP, 98% [80-100]; nfvPPA-CBD, 81% [65-98]; P = .08) were found in the nfvPPA-CBD group. At follow-up after 1 year, we observed no significant differences in any speech or language measures. Furthermore, atrophy in patients with PSP progressed within the subcortical/brainstem motor system generating greater oculomotors deficits and swallowing difficulty; atrophy in patients with CBD spread anteriorly in prefrontal regions consistent with their greater working memory impairment and development of behavioral symptoms.Conclusions and relevanceIn patients presenting with nfvPPA, presence of early severe dysarthria, relatively selective white matter atrophy at presentation, and a greater rate of change in the brainstem measured by longitudinal imaging may be useful for differentiating underlying PSP from CBD pathology during life.

Project description:Corticobasal degeneration (CBD) is a clinically heterogeneous tauopathy, which has overlapping clinicopathologic and genetic characteristics with progressive supranuclear palsy (PSP). This study aimed to elucidate whether transactive response DNA-binding protein of 43 kDa (TDP-43) pathology contributes to clinicopathologic heterogeneity of CBD. Paraffin-embedded sections of the midbrain, pons, subthalamic nucleus, and basal forebrain from 187 autopsy-confirmed CBD cases were screened with immunohistochemistry for phospho-TDP-43. In cases with TDP-43 pathology, additional brain regions (i.e., precentral, cingulate, and superior frontal gyri, hippocampus, medulla, and cerebellum) were immunostained. Hierarchical clustering analysis was performed based on the topographical distribution and severity of TDP-43 pathology, and clinicopathologic and genetic features were compared between the clusters. TDP-43 pathology was observed in 45% of CBD cases, most frequently in midbrain tegmentum (80% of TDP-43-positive cases), followed by subthalamic nucleus (69%). TDP-43-positive CBD was divided into TDP-limited (52%) and TDP-severe (48%) by hierarchical clustering analysis. TDP-severe patients were more likely to have been diagnosed clinically as PSP compared to TDP-limited and TDP-negative patients (80 vs 32 vs 30%, P < 0.001). The presence of downward gaze palsy was the strongest factor for the antemortem diagnosis of PSP, and severe TDP-43 pathology in the midbrain tectum was strongly associated with downward gaze palsy. In addition, tau burden in the olivopontocerebellar system was significantly greater in TDP-positive than TDP-negative CBD. Genetic analyses revealed that MAPT H1/H1 genotype frequency was significantly lower in TDP-severe than in TDP-negative and TDP-limited CBD (65 vs 89 vs 91%, P < 0.001). The homozygous minor allele frequencies in GRN rs5848 and TMEM106B rs3173615 were not significantly different between the three groups. In conclusion, the present study indicates that CBD with severe TDP-43 pathology is a distinct clinicopathologic subtype of CBD, characterized by PSP-like clinical presentations, severe tau pathology in the olivopontocerebellar system, and low frequency of MAPT H1 haplotype.

Dataset Information

Linkage disequilibrium fine mapping and haplotype association analysis of the tau gene in progressive supranuclear palsy and corticobasal degeneration.

Publications

Linkage disequilibrium fine mapping and haplotype association analysis of the tau gene in progressive supranuclear palsy and corticobasal degeneration.

Similar Datasets

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