Cancer and Vascular Comorbidity Effects on Dementia Risk and Neuropathology in the Oldest-Old.

BACKGROUND: Dementia, vascular disease, and cancer increase with age, enabling complex comorbid interactions. Understanding vascular and cancer contributions to dementia risk and neuropathology in oldest-old may improve risk modification and outcomes. OBJECTIVE: Investigate the contributions of vascular factors and cancer to dementia and neuropathology. METHODS: Longitudinal clinicopathologic study of prospectively followed Mayo Clinic participants dying≥95 years-old who underwent autopsy. Participants were stratified by dementia status and compared according to demographics, vascular risk factors, cancer, and neuropathology. RESULTS: Participants (n = 161; 83% female; 99% non-Hispanic whites)≥95 years (95-106 years-old) with/without dementia did not differ based on demographics. APOE ɛ2 frequency was higher in no dementia (20/72 [28%]) versus dementia (11/88 [12%]; p = 0.03), but APOE ɛ4 frequency did not differ. Coronary artery disease was more frequent in no dementia (31/72 [43%]) versus dementia (23/89 [26%]; p = 0.03) associated with 56% lower dementia odds (odds ratio [OR] = 0.44 [confidence interval (CI) = 0.19-0.98]; p = 0.04) and fewer neuritic/diffuse plaques. Diabetes had an 8-fold increase in dementia odds (OR = 8.42 [CI = 1.39-163]; p = 0.02). Diabetes associated with higher cerebrovascular disease (Dickson score; p = 0.05). Cancer associated with 63% lower dementia odds (OR = 0.37 [CI = 0.17-0.78]; p < 0.01) and lower Braak stage (p = 0.01). CONCLUSION: Cancer exposure in the oldest-old was associated with lower odds of dementia and tangle pathology, whereas history of coronary artery disease was associated with lower odds of dementia and amyloid-ß plaque pathology. History of diabetes mellitus was associated with increased odds of dementia and cerebrovascular disease pathology. Cancer-related mechanisms and vascular risk factor reduction strategies may alter dementia risk and neuropathology in oldest-old.

Increased prevalence of autoimmune disease within C9 and FTD/MND cohorts: Completing the picture.

OBJECTIVE: To determine the prevalence of autoimmune disease in symptomatic C9ORF72 (C9) mutation carriers and frontotemporal dementia with motor neuron disease (FTD/MND) cohorts. METHODS: In this case-control study, we reviewed the clinical histories of 66 patients with FTD/MND and 57 symptomatic C9 carriers (24 overlapping cases), a total of 99 charts, for history of autoimmune disease. The prevalence of autoimmune disease in C9 and FTD/MND cohorts was determined by χ2 and Fisher exact comparisons between the combined C9 and FTD/MND group with normal control, Alzheimer disease, and progressive supranuclear palsy cohorts, as well as comparisons within C9 and FTD/MND cohorts. RESULTS: Our combined C9 and FTD/MND cohort has a 12% prevalence of nonthyroid autoimmune disease. The prevalence of nonthyroid autoimmune disease in C9 and FTD/MND is similar to the rates in previously detailed progranulin and semantic variant primary progressive aphasia cohorts and elevated in comparison to previously collected normal control and typical Alzheimer disease cohorts, as well as a newly screened progressive supranuclear palsy cohort. Furthermore, the types of autoimmune disease in this combined C9 and FTD/MND cohort cluster within the same 3 categories previously described in progranulin and semantic variant primary progressive aphasia: inflammatory arthritides, cutaneous conditions, and gastrointestinal disorders. CONCLUSIONS: The association between selective autoimmune disease and neurodegenerative disorders unified by the underlying pathology frontotemporal lobar degeneration with TDP-43-positive inclusions (FTLD-TDP) extends to C9 and FTD/MND cohorts, providing further evidence that select autoimmune inflammation may be intrinsically linked to FTLD-TDP pathophysiology.

Case Studies Illustrating Focal Alzheimer's, Fluent Aphasia, Late-Onset Memory Loss, and Rapid Dementia.

Many dementia subtypes have more shared signs and symptoms than defining ones. We review 8 cases with 4 overlapping syndromes and demonstrate how to distinguish the cases. These include focal cortical presentations of Alzheimer's disease (AD; posterior cortical atrophy and corticobasal syndrome [CBS]), fluent aphasia (semantic dementia and logopenic aphasia), late-onset slowly progressive dementia (hippocampal sclerosis and limbic predominant AD) and rapidly progressive dementia (Creutzfeldt-Jakob disease and limbic encephalitis). Recognizing the different syndromes can help the clinician to improve their diagnostic skills, leading to improved patient outcomes by early and accurate diagnosis, prompt treatment, and appropriate counseling and guidance.

Evaluating pathogenic dementia variants in posterior cortical atrophy.

Posterior cortical atrophy (PCA) is an understudied visual impairment syndrome most often due to "posterior Alzheimer's disease (AD)" pathology. Case studies detected mutations in PSEN1, PSEN2, GRN, MAPT, and PRNP in subjects with clinical PCA. To detect the frequency and spectrum of mutations in known dementia genes in PCA, we screened 124 European-American subjects with clinical PCA (n = 67) or posterior AD neuropathology (n = 57) for variants in genes implicated in AD, frontotemporal dementia, and prion disease using NeuroX, a customized exome array. Frequencies in PCA of the variants annotated as pathogenic or potentially pathogenic were compared against ∼ 4300 European-American population controls from the NHLBI Exome Sequencing Project. We identified 2 rare variants not previously reported in PCA, TREM2 Arg47His, and PSEN2 Ser130Leu. No other pathogenic or potentially pathogenic variants were detected in the screened dementia genes. In this first systematic variant screen of a PCA cohort, we report 2 rare mutations in TREM2 and PSEN2, validate our previously reported APOE ε4 association, and demonstrate the utility of NeuroX.