The National Institute on Aging and the Alzheimer's Association charged a workgroup with the task of revising the 1984 criteria for Alzheimer's disease (AD) dementia. The workgroup sought to ensure that the revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available. We present criteria for all-cause dementia and for AD dementia. We retained the general framework of probable AD dementia from the 1984 criteria. On the basis of the past 27 years of experience, we made several changes in the clinical criteria for the diagnosis. We also retained the term possible AD dementia, but redefined it in a manner more focused than before. Biomarker evidence was also integrated into the diagnostic formulations for probable and possible AD dementia for use in research settings. The core clinical criteria for AD dementia will continue to be the cornerstone of the diagnosis in clinical practice, but biomarker evidence is expected to enhance the pathophysiological specificity of the diagnosis of AD dementia. Much work lies ahead for validating the biomarker diagnosis of AD dementia.

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The diagnosis of dementia due to Alzheimer’s disease: Recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer's disease

Rapid progress in deciphering the biological mechanism of Alzheimer's disease (AD) has arisen from the application of molecular and cell biology to this complex disorder of the limbic and association cortices. In turn, new insights into fundamental aspects of protein biology have resulted from research on the disease. This beneficial interplay between basic and applied cell biology is well illustrated by advances in understanding the genotype-to-phenotype relationships of familial Alzheimer's disease. All four genes definitively linked to inherited forms of the disease to date have been shown to increase the production and/or deposition of amyloid β-protein in the brain. In particular, evidence that the presenilin proteins, mutations in which cause the most aggressive form of inherited AD, lead to altered intramembranous cleavage of the β-amyloid precursor protein by the protease called γ-secretase has spurred progress toward novel therapeutics. The finding that presenilin itself may be the long-sought γ-...

Alzheimer's Disease: Genes, Proteins, and Therapy

Ubiquitin-positive, tau- and alpha-synuclein-negative inclusions are hallmarks of frontotemporal lobar degeneration with ubiquitin-positive inclusions and amyotrophic lateral sclerosis. Although the identity of the ubiquitinated protein specific to either disorder was unknown, we showed that TDP-43 is the major disease protein in both disorders. Pathologic TDP-43 was hyper-phosphorylated, ubiquitinated, and cleaved to generate C-terminal fragments and was recovered only from affected central nervous system regions, including hippocampus, neocortex, and spinal cord. TDP-43 represents the common pathologic substrate linking these neurodegenerative disorders.

http://science.sciencemag.org/content/sci/314/5796/130.full.pdf

Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis

Objective: To improve clinical recognition and provide research diagnostic criteria for three clinical syndromes associated with frontotemporal lobar degeneration. Methods: Consensus criteria for the three prototypic syndromes-frontotemporal dementia, progressive nonfluent aphasia, and semantic dementia-were developed by members of an international workshop on frontotemporal lobar degeneration. These criteria build on earlier published clinical diagnostic guidelines for frontotemporal dementia produced by some of the workshop members. Results: The consensus criteria specify core and supportive features for each of the three prototypic clinical syndromes and provide broad inclusion and exclusion criteria for the generic entity of frontotemporal lobar degeneration. The criteria are presented in lists, and operational definitions for features are provided in the text. Conclusions: The criteria ought to provide the foundation for research work into the neuropsychology, neuropathology, genetics, molecular biology, and epidemiology of these important clinical disorders that account for a substantial proportion of cases of primary degenerative dementia occurring before the age of 65 years.

Frontotemporal lobar degeneration A consensus on clinical diagnostic criteria

Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, 'possible' behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). 'Probable' behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia 'with definite frontotemporal lobar degeneration' requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer's disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met 'possible' criteria, and 104 (76%) met criteria for 'probable' behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with 'possible' and 'probable' criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.

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Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia.

Thirteen families have been described with an autosomal dominantly inherited dementia named frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17)(1-9), historically termed Pick's disease(10) Most FTDP-17 cases show neuronal and/or glial inclusions that stain positively with antibodies raised against the microtubule-associated protein Tau, although the Tau pathology varies considerably in both its quantity (or severity) and characteristics(1-8,12) Previous studies have mapped the FTDP-17 locus to a 2-centimorgan region on chromosome 17q2111; the tau gene also lies within this region We have now sequenced tau in FTDP-17 families and identified three missense mutations (G272V, P301L and R406W) and three mutations in the 5' splice site of exon in The splice-site mutations all destabilize a potential stem-loop structure which is probably involved in regulating the alternative splicing of exon10 (ref 13) This causes more frequent usage of the 5' splice site and an increased proportion of tan transcripts that include exon 10 The increase in exon 10(+) messenger RNA will increase the proportion of Tau containing four microtubule-binding repeats, which is consistent with the neuropathology described in several families with FTDP-17 (refs 12, 14)

Lien Kuei Che

Papers

Association of missense and 5′-splice-site mutations in tau with the inherited dementia FTDP-17