Browsing by Author "Gordon, Brian"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Change in Cerebrospinal Fluid Tau Microtubule Binding Region Detects Symptom Onset, Cognitive Decline, Tangles, and Atrophy in Dominantly Inherited Alzheimer's Disease
    (Wiley, 2023) Horie, Kanta; Li, Yan; Barthélemy, Nicolas R.; Gordon, Brian; Hassenstab, Jason; Benzinger, Tammie L. S.; Fagan, Anne M.; Morris, John C.; Karch, Celeste M.; Xiong, Chengjie; Allegri, Ricardo; Mendez, Patricio Chrem; Ikeuchi, Takeshi; Kasuga, Kensaku; Noble, James; Farlow, Martin; Chhatwal, Jasmeer; Day, Gregory; Schofield, Peter R.; Masters, Colin L.; Levin, Johannes; Jucker, Mathias; Lee, Jae-Hong; Roh, Jee Hoon; Sato, Chihiro; Sachdev, Pallavi; Koyama, Akihiko; Reyderman, Larisa; Bateman, Randall J.; McDade, Eric; Dominantly Inherited Alzheimer Network; Neurology, School of Medicine
    Objective: Identifying cerebrospinal fluid measures of the microtubule binding region of tau (MTBR-tau) species that reflect tau aggregation could provide fluid biomarkers that track Alzheimer's disease related neurofibrillary tau pathological changes. We examined the cerebrospinal fluid (CSF) MTBR-tau species in dominantly inherited Alzheimer's disease (DIAD) mutation carriers to assess the association with Alzheimer's disease (AD) biomarkers and clinical symptoms. Methods: Cross-sectional and longitudinal CSF from 229 DIAD mutation carriers and 130 mutation non-carriers had sequential characterization of N-terminal/mid-domain phosphorylated tau (p-tau) followed by MTBR-tau species and tau positron emission tomography (tau PET), other soluble tau and amyloid biomarkers, comprehensive clinical and cognitive assessments, and brain magnetic resonance imaging of atrophy. Results: CSF MTBR-tau species located within the putative "border" region and one species corresponding to the "core" region of aggregates in neurofibrillary tangles (NFTs) increased during the presymptomatic stage and decreased during the symptomatic stage. The "border" MTBR-tau species were associated with amyloid pathology and CSF p-tau; whereas the "core" MTBR-tau species were associated stronger with tau PET and CSF measures of neurodegeneration. The ratio of the border to the core species provided a continuous measure of increasing amounts that tracked clinical progression and NFTs. Interpretation: Changes in CSF soluble MTBR-tau species preceded the onset of dementia, tau tangle increase, and atrophy in DIAD. The ratio of 4R-specific MTBR-tau (border) to the NFT (core) MTBR-tau species corresponds to the pathology of NFTs in DIAD and change with disease progression. The dynamics between different MTBR-tau species in the CSF may serve as a marker of tau-related disease progression and target engagement of anti-tau therapeutics.
  • Thumbnail Image
    Item
    Comparing amyloid-β plaque burden with antemortem PiB PET in autosomal dominant and late-onset Alzheimer disease
    (Springer, 2021) Chen, Charles D.; Joseph-Mathurin, Nelly; Sinha, Namita; Zhou, Aihong; Li, Yan; Friedrichsen, Karl; McCullough, Austin; Franklin, Erin E.; Hornbeck, Russ; Gordon, Brian; Sharma, Vijay; Cruchaga, Carlos; Goate, Alison; Karch, Celeste; McDade, Eric; Xiong, Chengjie; Bateman, Randall J.; Ghetti, Bernardino; Ringman, John M.; Chhatwal, Jasmeer; Masters, Colin L.; McLean, Catriona; Lashley, Tammaryn; Su, Yi; Koeppe, Robert; Jack, Clifford; Klunk, William E.; Morris, John C.; Perrin, Richard J.; Cairns, Nigel J.; Benzinger, Tammie L.S.; Pathology and Laboratory Medicine, School of Medicine
    Pittsburgh compound B (PiB) radiotracer for positron emission tomography (PET) imaging can bind to different types of amyloid-β plaques and blood vessels (cerebral amyloid angiopathy). However, the relative contributions of different plaque subtypes (diffuse versus cored/compact) to in vivo PiB PET signal on a region-by-region basis is incompletely understood. Of particular interest is whether the same staging schemes for summarizing amyloid-β burden are appropriate for both late-onset and autosomal dominant forms of Alzheimer disease (LOAD and ADAD). Here we compared antemortem PiB PET with follow-up postmortem estimation of amyloid-β burden using stereologic methods to estimate the relative area fraction of diffuse and cored/compact amyloid-β plaques across 16 brain regions in 15 individuals with ADAD and 14 individuals with LOAD. In ADAD, we found that PiB PET correlated with diffuse plaques in the frontal, parietal, temporal, and striatal regions commonly used to summarize amyloid-β burden in PiB PET, and correlated with both diffuse and cored/compact plaques in the occipital lobe and parahippocampal gyrus. In LOAD, we found that PiB PET correlated with both diffuse and cored/compact plaques in the anterior cingulate, frontal lobe (middle frontal gyrus), and parietal lobe, and showed additional correlations with diffuse plaque in the amygdala and occipital lobe, and with cored/compact plaque in the temporal lobe. Thus, commonly used PiB PET summary regions predominantly reflect diffuse plaque burden in ADAD and a mixture of diffuse and cored/compact plaque burden in LOAD. In direct comparisons of ADAD and LOAD, postmortem stereology identified much greater mean amyloid-β plaque burdens in ADAD versus LOAD across almost all brain regions studied. However, standard PiB PET did not recapitulate these stereologic findings, likely due to non-trivial amyloid-β plaque burdens in ADAD within the cerebellum and brainstem – commonly used reference regions in PiB PET. Our findings suggest that PiB PET summary regions correlate with amyloid-β plaque burden in both ADAD and LOAD; however, they might not be reliable in direct comparisons of regional amyloid-β plaque burden between the two forms of AD.
  • Thumbnail Image
    Item
    First presentation with neuropsychiatric symptoms in autosomal dominant Alzheimer's disease: the Dominantly Inherited Alzheimer's Network Study
    (BMJ, 2023) O'Connor, Antoinette; Rice, Helen; Barnes, Josephine; Ryan, Natalie S.; Liu, Kathy Y.; Allegri, Ricardo Francisco; Berman, Sarah; Ringman, John M.; Cruchaga, Carlos; Farlow, Martin R.; Hassenstab, Jason; Lee, Jae-Hong; Perrin, Richard J.; Xiong, Chengjie; Gordon, Brian; Levey, Allan I.; Goate, Alison; Graff-Radford, Neil; Levin, Johannes; Jucker, Mathias; Benzinger, Tammie; McDade, Eric; Mori, Hiroshi; Noble, James M.; Schofield, Peter R.; Martins, Ralph N.; Salloway, Stephen; Chhatwal, Jasmeer; Morris, John C.; Bateman, Randall; Howard, Rob; Reeves, Suzanne; Fox, Nick C.; Dominantly Inherited Alzheimer Network; Neurology, School of Medicine
  • Thumbnail Image
    Item
    Longitudinal clinical, cognitive and biomarker profiles in dominantly inherited versus sporadic early-onset Alzheimer's disease
    (Oxford University Press, 2023-10-18) Llibre-Guerra, Jorge J.; Iaccarino, Leonardo; Coble, Dean; Edwards, Lauren; Li, Yan; McDade, Eric; Strom, Amelia; Gordon, Brian; Mundada, Nidhi; Schindler, Suzanne E.; Tsoy, Elena; Ma, Yinjiao; Lu, Ruijin; Fagan, Anne M.; Benzinger, Tammie L. S.; Soleimani-Meigooni, David; Aschenbrenner, Andrew J.; Miller, Zachary; Wang, Guoqiao; Kramer, Joel H.; Hassenstab, Jason; Rosen, Howard J.; Morris, John C.; Miller, Bruce L.; Xiong, Chengjie; Perrin, Richard J.; Allegri, Ricardo; Chrem, Patricio; Surace, Ezequiel; Berman, Sarah B.; Chhatwal, Jasmeer; Masters, Colin L.; Farlow, Martin R.; Jucker, Mathias; Levin, Johannes; Fox, Nick C.; Day, Gregory; Gorno-Tempini, Maria Luisa; Boxer, Adam L.; La Joie, Renaud; Rabinovici, Gil D.; Bateman, Randall; Neurology, School of Medicine
    Approximately 5% of Alzheimer's disease cases have an early age at onset (<65 years), with 5-10% of these cases attributed to dominantly inherited mutations and the remainder considered as sporadic. The extent to which dominantly inherited and sporadic early-onset Alzheimer's disease overlap is unknown. In this study, we explored the clinical, cognitive and biomarker profiles of early-onset Alzheimer's disease, focusing on commonalities and distinctions between dominantly inherited and sporadic cases. Our analysis included 117 participants with dominantly inherited Alzheimer's disease enrolled in the Dominantly Inherited Alzheimer Network and 118 individuals with sporadic early-onset Alzheimer's disease enrolled at the University of California San Francisco Alzheimer's Disease Research Center. Baseline differences in clinical and biomarker profiles between both groups were compared using t-tests. Differences in the rates of decline were compared using linear mixed-effects models. Individuals with dominantly inherited Alzheimer's disease exhibited an earlier age-at-symptom onset compared with the sporadic group [43.4 (SD ± 8.5) years versus 54.8 (SD ± 5.0) years, respectively, P < 0.001]. Sporadic cases showed a higher frequency of atypical clinical presentations relative to dominantly inherited (56.8% versus 8.5%, respectively) and a higher frequency of APOE-ε4 (50.0% versus 28.2%, P = 0.001). Compared with sporadic early onset, motor manifestations were higher in the dominantly inherited cohort [32.5% versus 16.9% at baseline (P = 0.006) and 46.1% versus 25.4% at last visit (P = 0.001)]. At baseline, the sporadic early-onset group performed worse on category fluency (P < 0.001), Trail Making Test Part B (P < 0.001) and digit span (P < 0.001). Longitudinally, both groups demonstrated similar rates of cognitive and functional decline in the early stages. After 10 years from symptom onset, dominantly inherited participants experienced a greater decline as measured by Clinical Dementia Rating Sum of Boxes [3.63 versus 1.82 points (P = 0.035)]. CSF amyloid beta-42 levels were comparable [244 (SD ± 39.3) pg/ml dominantly inherited versus 296 (SD ± 24.8) pg/ml sporadic early onset, P = 0.06]. CSF phosphorylated tau at threonine 181 levels were higher in the dominantly inherited Alzheimer's disease cohort (87.3 versus 59.7 pg/ml, P = 0.005), but no significant differences were found for t-tau levels (P = 0.35). In summary, sporadic and inherited Alzheimer's disease differed in baseline profiles; sporadic early onset is best distinguished from dominantly inherited by later age at onset, high frequency of atypical clinical presentations and worse executive performance at baseline. Despite these differences, shared pathways in longitudinal clinical decline and CSF biomarkers suggest potential common therapeutic targets for both populations, offering valuable insights for future research and clinical trial design.
  • Thumbnail Image
    Item
    Longitudinal head-to-head comparison of 11C-PiB and 18F-florbetapir PET in a Phase 2/3 clinical trial of anti-amyloid-β monoclonal antibodies in dominantly inherited Alzheimer disease
    (Springer, 2023) Chen, Charles D.; McCullough, Austin; Gordon, Brian; Joseph-Mathurin, Nelly; Flores, Shaney; McKay, Nicole S.; Hobbs, Diana A.; Hornbeck, Russ; Fagan, Anne M.; Cruchaga, Carlos; Goate, Alison M.; Perrin, Richard J.; Wang, Guoqiao; Li, Yan; Shi, Xinyu; Xiong, Chengjie; Pontecorvo, Michael J.; Klein, Gregory; Su, Yi; Klunk, William E.; Jack, Clifford; Koeppe, Robert; Snider, B. Joy; Berman, Sarah B.; Roberson, Erik D.; Brosch, Jared; Surti, Ghulam; Jiménez-Velázquez, Ivonne Z.; Galasko, Douglas; Honig, Lawrence S.; Brooks, William S.; Clarnette, Roger; Wallon, David; Dubois, Bruno; Pariente, Jérémie; Pasquier, Florence; Sanchez-Valle, Raquel; Shcherbinin, Sergey; Higgins, Ixavier; Tunali, Ilke; Masters, Colin L.; van Dyck, Christopher H.; Masellis, Mario; Hsiung, Robin; Gauthier, Serge; Salloway, Steve; Clifford, David B.; Mills, Susan; Supnet-Bell, Charlene; McDade, Eric; Bateman, Randall J.; Benzinger, Tammie L. S.; DIAN-TU Study Team; Neurology, School of Medicine
    Purpose: Pittsburgh Compound-B (11C-PiB) and 18F-florbetapir are amyloid-β (Aβ) positron emission tomography (PET) radiotracers that have been used as endpoints in Alzheimer's disease (AD) clinical trials to evaluate the efficacy of anti-Aβ monoclonal antibodies. However, comparing drug effects between and within trials may become complicated if different Aβ radiotracers were used. To study the consequences of using different Aβ radiotracers to measure Aβ clearance, we performed a head-to-head comparison of 11C-PiB and 18F-florbetapir in a Phase 2/3 clinical trial of anti-Aβ monoclonal antibodies. Methods: Sixty-six mutation-positive participants enrolled in the gantenerumab and placebo arms of the first Dominantly Inherited Alzheimer Network Trials Unit clinical trial (DIAN-TU-001) underwent both 11C-PiB and 18F-florbetapir PET imaging at baseline and during at least one follow-up visit. For each PET scan, regional standardized uptake value ratios (SUVRs), regional Centiloids, a global cortical SUVR, and a global cortical Centiloid value were calculated. Longitudinal changes in SUVRs and Centiloids were estimated using linear mixed models. Differences in longitudinal change between PET radiotracers and between drug arms were estimated using paired and Welch two sample t-tests, respectively. Simulated clinical trials were conducted to evaluate the consequences of some research sites using 11C-PiB while other sites use 18F-florbetapir for Aβ PET imaging. Results: In the placebo arm, the absolute rate of longitudinal change measured by global cortical 11C-PiB SUVRs did not differ from that of global cortical 18F-florbetapir SUVRs. In the gantenerumab arm, global cortical 11C-PiB SUVRs decreased more rapidly than global cortical 18F-florbetapir SUVRs. Drug effects were statistically significant across both Aβ radiotracers. In contrast, the rates of longitudinal change measured in global cortical Centiloids did not differ between Aβ radiotracers in either the placebo or gantenerumab arms, and drug effects remained statistically significant. Regional analyses largely recapitulated these global cortical analyses. Across simulated clinical trials, type I error was higher in trials where both Aβ radiotracers were used versus trials where only one Aβ radiotracer was used. Power was lower in trials where 18F-florbetapir was primarily used versus trials where 11C-PiB was primarily used. Conclusion: Gantenerumab treatment induces longitudinal changes in Aβ PET, and the absolute rates of these longitudinal changes differ significantly between Aβ radiotracers. These differences were not seen in the placebo arm, suggesting that Aβ-clearing treatments may pose unique challenges when attempting to compare longitudinal results across different Aβ radiotracers. Our results suggest converting Aβ PET SUVR measurements to Centiloids (both globally and regionally) can harmonize these differences without losing sensitivity to drug effects. Nonetheless, until consensus is achieved on how to harmonize drug effects across radiotracers, and since using multiple radiotracers in the same trial may increase type I error, multisite studies should consider potential variability due to different radiotracers when interpreting Aβ PET biomarker data and, if feasible, use a single radiotracer for the best results.
  • Thumbnail Image
    Item
    Molecular neuroimaging in dominantly inherited versus sporadic early-onset Alzheimer's disease
    (Oxford University Press, 2024-05-03) Iaccarino, Leonardo; Llibre-Guerra, Jorge J.; McDade, Eric; Edwards, Lauren; Gordon, Brian; Benzinger, Tammie; Hassenstab, Jason; Kramer, Joel H.; Li, Yan; Miller, Bruce L.; Miller, Zachary; Morris, John C.; Mundada, Nidhi; Perrin, Richard J.; Rosen, Howard J.; Soleimani-Meigooni, David; Strom, Amelia; Tsoy, Elena; Wang, Guoqiao; Xiong, Chengjie; Allegri, Ricardo; Chrem, Patricio; Vazquez, Silvia; Berman, Sarah B.; Chhatwal, Jasmeer; Masters, Colin L.; Farlow, Martin R.; Jucker, Mathias; Levin, Johannes; Salloway, Stephen; Fox, Nick C.; Day, Gregory S.; Gorno-Tempini, Maria Luisa; Boxer, Adam L.; La Joie, Renaud; Bateman, Randall; Rabinovici, Gil D.; Neurology, School of Medicine
    Approximately 5% of Alzheimer's disease patients develop symptoms before age 65 (early-onset Alzheimer's disease), with either sporadic (sporadic early-onset Alzheimer's disease) or dominantly inherited (dominantly inherited Alzheimer's disease) presentations. Both sporadic early-onset Alzheimer's disease and dominantly inherited Alzheimer's disease are characterized by brain amyloid-β accumulation, tau tangles, hypometabolism and neurodegeneration, but differences in topography and magnitude of these pathological changes are not fully elucidated. In this study, we directly compared patterns of amyloid-β plaque deposition and glucose hypometabolism in sporadic early-onset Alzheimer's disease and dominantly inherited Alzheimer's disease individuals. Our analysis included 134 symptomatic sporadic early-onset Alzheimer's disease amyloid-Positron Emission Tomography (PET)-positive cases from the University of California, San Francisco, Alzheimer's Disease Research Center (mean ± SD age 59.7 ± 5.6 years), 89 symptomatic dominantly inherited Alzheimer's disease cases (age 45.8 ± 9.3 years) and 102 cognitively unimpaired non-mutation carriers from the Dominantly Inherited Alzheimer Network study (age 44.9 ± 9.2). Each group underwent clinical and cognitive examinations, 11C-labelled Pittsburgh Compound B-PET and structural MRI. 18F-Fluorodeoxyglucose-PET was also available for most participants. Positron Emission Tomography scans from both studies were uniformly processed to obtain a standardized uptake value ratio (PIB50-70 cerebellar grey reference and FDG30-60 pons reference) images. Statistical analyses included pairwise global and voxelwise group comparisons and group-independent component analyses. Analyses were performed also adjusting for covariates including age, sex, Mini-Mental State Examination, apolipoprotein ε4 status and average composite cortical of standardized uptake value ratio. Compared with dominantly inherited Alzheimer's disease, sporadic early-onset Alzheimer's disease participants were older at age of onset (mean ± SD, 54.8 ± 8.2 versus 41.9 ± 8.2, Cohen's d = 1.91), with more years of education (16.4 ± 2.8 versus 13.5 ± 3.2, d = 1) and more likely to be apolipoprotein ε4 carriers (54.6% ε4 versus 28.1%, Cramer's V = 0.26), but similar Mini-Mental State Examination (20.6 ± 6.1 versus 21.2 ± 7.4, d = 0.08). Sporadic early-onset Alzheimer's disease had higher global cortical Pittsburgh Compound B-PET binding (mean ± SD standardized uptake value ratio, 1.92 ± 0.29 versus 1.58 ± 0.44, d = 0.96) and greater global cortical 18F-fluorodeoxyglucose-PET hypometabolism (mean ± SD standardized uptake value ratio, 1.32 ± 0.1 versus 1.39 ± 0.19, d = 0.48) compared with dominantly inherited Alzheimer's disease. Fully adjusted comparisons demonstrated relatively higher Pittsburgh Compound B-PET standardized uptake value ratio in the medial occipital, thalami, basal ganglia and medial/dorsal frontal regions in dominantly inherited Alzheimer's disease versus sporadic early-onset Alzheimer's disease. Sporadic early-onset Alzheimer's disease showed relatively greater 18F-fluorodeoxyglucose-PET hypometabolism in Alzheimer's disease signature temporoparietal regions and caudate nuclei, whereas dominantly inherited Alzheimer's disease showed relatively greater hypometabolism in frontal white matter and pericentral regions. Independent component analyses largely replicated these findings by highlighting common and unique Pittsburgh Compound B-PET and 18F-fluorodeoxyglucose-PET binding patterns. In summary, our findings suggest both common and distinct patterns of amyloid and glucose hypometabolism in sporadic and dominantly inherited early-onset Alzheimer's disease.
  • Thumbnail Image
    Item
    Serum neurofilament dynamics predicts neurodegeneration and clinical progression in presymptomatic Alzheimer's disease
    (Nature Research, 2019-02) Preische, Oliver; Schultz, Stephanie A.; Apel, Anja; Kuhle, Jens; Kaeser, Stephan A.; Barro, Christian; Gräber, Susanne; Kuder-Buletta, Elke; LaFougere, Christian; Laske, Christoph; Vöglein, Jonathan; Levin, Johannes; Masters, Colin L.; Martins, Ralph; Schofield, Peter R.; Rossor, Martin N.; Graff-Radford, Neill R.; Salloway, Stephen; Ghetti, Bernardino; Ringman, John M.; Noble, James M.; Chhatwal, Jasmeer; Goate, Alison M.; Benzinger, Tammie L. S.; Morris, John C.; Bateman, Randall J.; Wang, Guoqiao; Fagan, Anne M.; McDade, Eric M.; Gordon, Brian A.; Jucker, Mathias; Alzheimer Network; Allegri, Ricardo; Amtashar, Fatima; Bateman, Randall; Benzinger, Tammie; Berman, Sarah; Bodge, Courtney; Brandon, Susan; Brooks, William; Buck, Jill; Buckles, Virginia; Chea, Sochenda; Chhatwal, Jasmeer; Chrem, Patricio; Chui, Helena; Cinco, Jake; Clifford, Jack; Cruchaga, Carlos; D’Mello, Mirelle; Donahue, Tamara; Douglas, Jane; Edigo, Noelia; Erekin-Taner, Nilufer; Fagan, Anne; Farlow, Marty; Farrar, Angela; Feldman, Howard; Flynn, Gigi; Fox, Nick; Franklin, Erin; Fujii, Hisako; Gant, Cortaiga; Gardener, Samantha; Ghetti, Bernardino; Goate, Alison; Goldman, Jill; Gordon, Brian; Graff-Radford, Neill; Gray, Julia; Gurney, Jenny; Hassenstab, Jason; Hirohara, Mie; Holtzman, David; Hornbeck, Russ; DiBari, Siri Houeland; Ikeuchi, Takeshi; Ikonomovic, Snezana; Jerome, Gina; Jucker, Mathias; Karch, Celeste; Kasuga, Kensaku; Kawarabayashi, Takeshi; Klunk, William; Koeppe, Robert; Kuder-Buletta, Elke; Laske, Christoph; Lee, Jae-Hong; Levin, Johannes; Marcus, Daniel; Martins, Ralph; Mason, Neal Scott; Masters, Colin; Maue-Dreyfus, Denise; McDade, Eric; Montoya, Lucy; Mori, Hiroshi; Morris, John; Nagamatsu, Akem; Neimeyer, Katie; Noble, James; Norton, Joanne; Perrin, Richard; Raichle, Marc; Ringman, John; Roh, Jee Hoon; Salloway, Stephen; Schofield, Peter; Shimada, Hiroyuki; Shiroto, Tomoyo; Shoji, Mikio; Sigurdson, Wendy; Sohrabi, Hamid; Sparks, Paige; Suzuki, Kazushi; Swisher, Laura; Taddei, Kevin; Wang, Jen; Wang, Peter; Weiner, Mike; Wolfsberger, Mary; Xiong, Chengjie; Xu, Xiong; Pathology and Laboratory Medicine, School of Medicine
    Neurofilament light chain (NfL) is a promising fluid biomarker of disease progression for various cerebral proteopathies. Here we leverage the unique characteristics of the Dominantly Inherited Alzheimer Network and ultrasensitive immunoassay technology to demonstrate that NfL levels in the cerebrospinal fluid (n = 187) and serum (n = 405) are correlated with one another and are elevated at the presymptomatic stages of familial Alzheimer's disease. Longitudinal, within-person analysis of serum NfL dynamics (n = 196) confirmed this elevation and further revealed that the rate of change of serum NfL could discriminate mutation carriers from non-mutation carriers almost a decade earlier than cross-sectional absolute NfL levels (that is, 16.2 versus 6.8 years before the estimated symptom onset). Serum NfL rate of change peaked in participants converting from the presymptomatic to the symptomatic stage and was associated with cortical thinning assessed by magnetic resonance imaging, but less so with amyloid-β deposition or glucose metabolism (assessed by positron emission tomography). Serum NfL was predictive for both the rate of cortical thinning and cognitive changes assessed by the Mini-Mental State Examination and Logical Memory test. Thus, NfL dynamics in serum predict disease progression and brain neurodegeneration at the early presymptomatic stages of familial Alzheimer's disease, which supports its potential utility as a clinically useful biomarker.