Progressive supranuclear palsy (PSP) is a movement disorder with prominent tau neuropathology. Brain diseases with abnormal tau deposits are called tauopathies, the most common being Alzheimer’s disease. Environmental causes of tauopathies include repetitive head trauma associated with some sports. To identify common genetic variation contributing to risk for tauopathies, we carried out a genome-wide association study of 1,114 PSP cases and 3,247 controls (Stage 1) followed up by a second stage where 1,051 cases and 3,560 controls were genotyped for Stage 1 SNPs that yielded P ≤ 10−3. We found significant novel signals (P < 5 × 10−8) associated with PSP risk at STX6, EIF2AK3, and MOBP. We confirmed two independent variants in MAPT affecting risk for PSP, one of which influences MAPT brain expression. The genes implicated encode proteins for vesicle-membrane fusion at the Golgi-endosomal interface, for the endoplasmic reticulum unfolded protein response, and for a myelin structural component.

Autopsy is the diagnostic gold standard for progressive supranuclear palsy (PSP). The National Institute of Neurological Disorders and Stroke and Society for Progressive Supranuclear Palsy (NINDS-SPSP) criteria for the clinical diagnosis of "probable" PSP are thought to possess high specificity and low sensitivity. The NINDS-SPSP criteria for "possible" PSP are considered to increase sensitivity at the expense of specificity. The Neuroprotection and Natural History in Parkinson Plus Syndromes (NNIPPS) criteria are intended to improve sensitivity while maintaining high specificity. The aim of this study was to conduct a clinicopathological evaluation of the NINDS-SPSP and NNIPPS criteria in tertiary neurological centers. Defined clinical features and their year of onset were recorded by chart review in neuropathologically diagnosed patients with PSP, Parkinsons's disease (PD), MSA parkinsonism and corticobasal degeneration from four European brain banks. Fulfillment of the clinical diagnostic criteria was verified for each year after disease onset and for the final antemortem record. We analyzed 98 PSP patients and 46 disease controls. The NINDS-SPSP "probable" criteria yielded shorter time to diagnosis, slightly higher specificity and positive predictive value (PPV), and similar sensitivity, compared with the NNIPPS criteria. Unexpectedly, the NINDS-SPSP "possible" criteria yielded the lowest sensitivity, specificity, and PPV. A combination of NINDS-SPSP possible and probable criteria yielded the highest sensitivity. We suggest that the NINDS-SPSP probable criteria might be preferred for recruitment of patients for clinical trials, where an early and specific diagnosis is important. For routine clinical care, where high sensitivity is crucial, a combination of NINDS possible and probable criteria might be preferred.

Frontotemporal lobar degeneration (FTLD) is a clinically, genetically and pathologically heterogeneous disorder. Within FTLD with ubiquitin-positive inclusions (FTLD-U), a new pathological subtype named FTLD-FUS was recently found with fused in sarcoma (FUS) positive, TDP-43-negative inclusions, and striking atrophy of the caudate nucleus. The aim of this study was to determine the frequency of FTLD-FUS in our pathological FTLD series, and to describe the clinical, neuroimaging and neuropathological features of FTLD-FUS, especially caudate atrophy. Demographic and clinical data collected prospectively from 387 patients with frontotemporal dementia (FTD) yielded 74 brain specimens. Immunostaining was carried out using a panel of antibodies, including AT-8, ubiquitin, p62, FUS, and TDP-43. Cortical and caudate atrophy on MRI (n = 136) was rated as normal, mild-moderate or severe. Of the 37 FTLD-U cases, 33 were reclassified as FTLD-TDP and four (0.11, 95%: 0.00–0.21) as FTLD-FUS, with ubiquitin and FUS-positive, p62 and TDP-43-negative neuronal intranuclear inclusions (NII). All four FTLD-FUS cases had a negative family history, behavioural variant FTD (bvFTD), and three had an age at onset ≤40 years. MRI revealed mild-moderate or severe caudate atrophy in all, with a mean duration from onset till MRI of 63 months (range 16–119 months). In our total clinical FTD cohort, we found 11 patients (0.03; 95% CI: 0.01–0.05) with bvFTD, negative family history, and age at onset ≤40 years. Caudate atrophy was present in 10 out of 136 MRIs, and included all four FUS-cases. The newly identified FTLD-FUS has a frequency of 11% in FTLD-U, and an estimated frequency of three percent in our clinical FTD cohort. The existence of this pathological subtype can be predicted with reasonable certainty by age at onset ≤40 years, negative family history, bvFTD and caudate atrophy on MRI.

International audienceAbstract Objective: To compare survival and to identify prognostic predictors for progressive supranuclear palsy and frontotemporal dementia. Background: PSP and FTD are related disorders. Homozygosity for H1 haplotype is associated with PSP, whereas several MAPT mutations have been identified in FTLD-tau. Survival duration probably reflects underlying pathophysiology or disease. Methods: Patients with PSP and FTD were recruited by nation-wide referral. Survival of 354 FTD patients was compared to that of 197 PSP patients. Cox regression analysis was performed to identify prognostic predictors. FTLD-tau was defined as Pick's disease and FTDP-17 with MAPT mutations. Semiquantitative evaluation of tau-positive pathology was performed on all pathologically proven cases. Results: Median survival of PSP patients (8.0 years; 95% CI 7.3 to 8.7) was significantly shorter than of FTD patients (9.9 years; 95% CI 9.2 to 10.6). Corrected for demographic differences, PSP patients were still significantly more at risk of dying than FTD patients. In PSP, male gender, older onset-age, and higher PSP Rating Scale score were identified as independent predictors for shorter survival, whereas in FTD a positive family history and an older onset-age were associated with a poor prognosis. The difference in hazard rate was even more pronounced when comparing pathologically proven cases of PSP with FTLD-tau. Conclusion: Survival of PSP patients is shorter than of FTD patients, and probably reflects a more aggressive disease process in PSP. Independent predictors of shorter survival in PSP were male gender, older onset-age and higher PSP rating scale score, whereas in FTD a positive family history and higher onset-age were predictors for worse prognosis

Pathological accumulation of intermediate filaments can be observed in neurodegenerative disorders, such as Alzheimer's disease, frontotemporal dementia and Parkinson's disease, and is also characteristic of neuronal intermediate filament inclusion disease. Intermediate filaments type IV include three neurofilament proteins (light, medium and heavy molecular weight neurofilament subunits) and α-internexin. The phosphorylation of intermediate filament proteins contributes to axonal growth, and is regulated by protein kinase A. Here we describe a family with a novel late-onset neurodegenerative disorder presenting with dementia and/or parkinsonism in 12 affected individuals. The disorder is characterized by a unique neuropathological phenotype displaying abundant neuronal inclusions by haematoxylin and eosin staining throughout the brain with immunoreactivity for intermediate filaments. Combining linkage analysis, exome sequencing and proteomics analysis, we identified a heterozygous c.149T>G (p.Leu50Arg) missense mutation in the gene encoding the protein kinase A type I-beta regulatory subunit (PRKAR1B). The pathogenicity of the mutation is supported by segregation in the family, absence in variant databases, and the specific accumulation of PRKAR1B in the inclusions in our cases associated with a specific biochemical pattern of PRKAR1B. Screening of PRKAR1B in 138 patients with Parkinson's disease and 56 patients with frontotemporal dementia did not identify additional novel pathogenic mutations. Our findings link a pathogenic PRKAR1B mutation to a novel hereditary neurodegenerative disorder and suggest an altered protein kinase A function through a reduced binding of the regulatory subunit to the A-kinase anchoring protein and the catalytic subunit of protein kinase A, which might result in subcellular dislocalization of the catalytic subunit and hyperphosphorylation of intermediate filaments.