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We characterized the world’s second case with ascertained extreme resilience to autosomal dominant Alzheimer’s disease (ADAD). Side-by-side comparisons of this male case and the previously reported female case with ADAD homozygote for the APOE3 Christchurch (APOECh) variant allowed us to discern common features. The male remained cognitively intact until 67 years of age despite carrying a PSEN1-E280A mutation. Like the APOECh carrier, he had extremely elevated amyloid plaque burden and limited entorhinal Tau tangle burden. He did not carry the APOECh variant but was heterozygous for a rare variant in RELN (H3447R, termed COLBOS after the Colombia–Boston biomarker research study), a ligand that like apolipoprotein E binds to the VLDLr and APOEr2 receptors. RELN-COLBOS is a gain-of-function variant showing stronger ability to activate its canonical protein target Dab1 and reduce human Tau phosphorylation in a knockin mouse. A genetic variant in a case protected from ADAD suggests a role for RELN signaling in resilience to dementia.

Objectives: Alzheimer’s disease (AD) is known to impact semantic access, which is frequently evaluated using the Category Fluency (Animals) test. Recent studies have suggested that in addition to overall category fluency scores (total number of words produced over time), poor clustering could signal AD-related cognitive difficulties. In this study, we examined the association between category fluency clustering performance (i.e., stating words sequentially that are all contained within a subcategory, such as domestic animals) and brain pathology in individuals with autosomal dominant Alzheimer’s disease (ADAD). Methods: A total of 29 non-demented carriers of the Presenilin1 E280A ADAD mutation and 32 noncarrier family members completed the category fluency test (Animals) and the Mini-Mental State Examination (MMSE). The participants also underwent positron emission tomography (PET) scans to evaluate in vivo amyloid-beta in the neocortex and tau in medial temporal lobe regions. Differences between carriers and noncarriers on cognitive tests were assessed with Mann-Whitney tests; associations between cognitive test performance and brain pathology were assessed with Spearman correlations. Results: Animal fluency scores did not differ between carriers and noncarriers. Carriers, however, showed a stronger association between animal fluency clustering and in vivo AD brain pathology (neocortical amyloid and entorhinal tau) relative to noncarriers. Conclusion: This study indicates that using category fluency clustering, but not total score, is related to AD pathophysiology in the preclinical and early stages of the disease.

Introduction Autopsy studies recognize the locus coeruleus (LC) as one of the first sites accumulating tau in Alzheimer's disease (AD). Recent AD work related in vivo LC magnetic resonance imaging (MRI) integrity to tau and cognitive decline; however, relationships of LC integrity to age, tau, and cognition in autosomal dominant AD (ADAD) remain unexplored. Methods We associated LC integrity (3T-MRI) with estimated years of onset, cortical amyloid beta, regional tau (positron emission tomography [PET]) and memory (Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word-List-Learning) among 27 carriers and 27 non-carriers of the presenilin-1 (PSEN1) E280A mutation. Longitudinal changes between LC integrity and tau were evaluated in 10 carriers. Results LC integrity started to decline at age 32 in carriers, 12 years before clinical onset, and 20 years earlier than in sporadic AD. LC integrity was negatively associated with cortical tau, independent of amyloid beta, and predicted precuneus tau increases. LC integrity was positively associated with memory. Discussion These findings support LC integrity as marker of disease progression in preclinical ADAD.

Background: Olfactory dysfunction is one of the earliest signs of Alzheimer’s disease (AD), highlighting its potential use as a biomarker for early detection. It has also been linked to progression from mild cognitive impairment (MCI) to dementia. Objective: To study olfactory function and its associations with markers of AD brain pathology in non-demented mutation carriers of an autosomal dominant AD (ADAD) mutation and non-carrier family members. Methods: We analyzed cross-sectional data from 16 non-demented carriers of the Presenilin1 E280A ADAD mutation (mean age [SD]: 40.1 [5.3], and 19 non-carrier family members (mean age [SD]: 36.0 [5.5]) from Colombia, who completed olfactory and cognitive testing and underwent amyloid and tau positron emission tomography (PET) imaging. Results: Worse olfactory identification performance was associated with greater age in mutation carriers (r = –0.52 p = 0.037). In carriers, worse olfactory identification performance was related to worse MMSE scores (r = 0.55, p = 0.024) and CERAD delayed recall (r = 0.63, p = 0.007) and greater cortical amyloid-β (r = –0.53, p = 0.042) and tau pathology burden (entorhinal: r = –0.59, p = 0.016; inferior temporal: r = –0.52, p = 0.038). Conclusion: Worse performance on olfactory identification tasks was associated with greater age, a proxy for disease progression in this genetically vulnerable ADAD cohort. In addition, this is the first study to report olfactory dysfunction in ADAD mutation carriers with diagnosis of MCI and its correlation with abnormal accumulation of tau pathology in the entorhinal region. Taken together, our findings suggest that olfactory dysfunction has promise as an early marker of brain pathology and future risk for dementia.

Plasma-measured tau phosphorylated at threonine 217 (p-tau217) is a potential non-invasive biomarker of Alzheimer's disease (AD). We investigated whether plasma p-tau217 predicts subsequent cognition and positron emission tomography (PET) markers of pathology in autosomal dominant AD.We analyzed baseline levels of plasma p-tau217 and its associations with amyloid PET, tau PET, and word list delayed recall measured 7.61 years later in non-demented age- and education-matched presenilin-1 E280A carriers (n = 24) and non-carrier (n = 20) family members.Carriers had higher plasma p-tau217 levels than non-carriers. Baseline plasma p-tau217 was associated with subsequent amyloid and tau PET pathology levels and cognitive function.Our findings suggest that plasma p-tau217 predicts subsequent brain pathological burden and memory performance in presenilin-1 E280A carriers. These results provide support for plasma p-tau217 as a minimally invasive diagnostic and prognostic biomarker for AD, with potential utility in clinical practice and trials.Non-demented presenilin-1 E280A carriers have higher plasma tau phosphorylated at threonine 217 (p-tau217) than do age-matched non-carriers. Higher baseline p-tau217 is associated with greater future amyloid positron emission tomography (PET) pathology burden. Higher baseline p-tau217 is associated with greater future tau PET pathology burden. Higher baseline p-tau217 is associated with worse future memory performance.

We describe in vivo follow-up PET imaging and postmortem findings from an autosomal dominant Alzheimer’s disease (ADAD) PSEN1 E280A carrier who was also homozygous for the APOE3 Christchurch (APOE3ch) variant and was protected against Alzheimer’s symptoms for almost three decades beyond the expected age of onset. We identified a distinct anatomical pattern of tau pathology with atypical accumulation in vivo and unusual postmortem regional distribution characterized by sparing in the frontal cortex and severe pathology in the occipital cortex. The frontal cortex and the hippocampus, less affected than the occipital cortex by tau pathology, contained Related Orphan Receptor B (RORB) positive neurons, homeostatic astrocytes and higher APOE expression. The occipital cortex, the only cortical region showing cerebral amyloid angiopathy (CAA), exhibited a distinctive chronic inflammatory microglial profile and lower APOE expression. Thus, the Christchurch variant may impact the distribution of tau pathology, modulate age at onset, severity, progression, and clinical presentation of ADAD, suggesting possible therapeutic strategies.

Background: Greater neuroticism has been associated with higher risk for Alzheimer’s disease (AD) dementia. However, the directionality of this association is unclear. We examined whether personality traits differ between cognitively-unimpaired carriers of autosomal-dominant AD (ADAD) and non-carriers, and are associated with in vivo AD pathology. Objective: To determine whether personality traits differ between cognitively unimpaired ADAD mutation carriers and non-carriers, and whether the traits are related to age and AD biomarkers. Methods: A total of 33 cognitively-unimpaired Presenilin-1 E280A mutation carriers and 41 non-carriers (ages 27–46) completed neuropsychological testing and the NEO Five-Factor Personality Inventory. A subsample (n = 46; 20 carriers) also underwent tau and amyloid PET imaging. Results: Carriers reported higher neuroticism relative to non-carriers, although this difference was not significant after controlling for sex. Neuroticism was positively correlated with entorhinal tau levels only in carriers, but not with amyloid levels. Conclusion: The finding of higher neuroticism in carriers and the association of this trait with tau pathology in preclinical stages of AD highlights the importance of including personality measures in the evaluation of individuals at increased risk for cognitive impairment and dementia. Further research is needed to characterize the mechanisms of these relationships.

Background Neurofilament light (NfL) is a promising biomarker of early neurodegeneration in Alzheimer's disease (AD). We examined whether plasma NfL was associated with in vivo amyloid beta and tau, and cognitive performance in non-demented presenilin-1 (PSEN1) E280A mutation carriers. Methods Twenty-five mutation carriers and 19 non-carriers (age range: 28 to 49 years) were included in this study. Participants underwent 11C Pittsburgh compound B (PiB)-PET (positron emission tomography), flortaucipir-PET, blood sampling, and cognitive testing. Results Mutation carriers exhibited higher plasma NfL levels than non-carriers. In carriers, higher NfL levels were related to greater regional tau burden and worse cognition, but not amyloid beta load. When we adjusted for age, a proxy of disease progression, elevated plasma NfL levels were only correlated with worse memory recall. Conclusions Findings support an association between plasma NfL, cognition, and tau pathology in non-demented individuals at genetic risk for developing AD dementia. Plasma NfL may be useful for selecting individuals at increased risk and tracking disease progression in AD.

The human brain is composed of functional networks that have a modular topology, where brain regions are organized into communities that form internally dense (segregated) and externally sparse (integrated) subnetworks that underlie higher-order cognitive functioning. It is hypothesized that amyloid-β and tau pathology in preclinical Alzheimer’s disease (AD) spread through functional networks, disrupting neural communication that results in cognitive dysfunction. We used high-resolution (voxel-level) graph-based network analyses to test whether in vivo amyloid-β and tau burden was associated with the segregation and integration of brain functional connections, and episodic memory, in cognitively unimpaired Presenilin-1 E280A carriers who are expected to develop early-onset AD dementia in ∼13 y on average. Compared to noncarriers, mutation carriers exhibited less functional segregation and integration in posterior default-mode network (DMN) regions, particularly the precuneus, and in the retrospenial cortex, which has been shown to link medial temporal regions and cortical regions of the DMN. Mutation carriers also showed greater functional segregation and integration in regions connected to the salience network, including the striatum and thalamus. Greater tau burden was associated with lower segregated and integrated functional connectivity of DMN regions, particularly the precuneus and medial prefrontal cortex. In turn, greater tau pathology was related to higher segregated and integrated functional connectivity in the retrospenial cortex and the anterior cingulate cortex, a hub of the salience network. These findings enlighten our understanding of how AD-related pathology distinctly alters the brain’s functional architecture in the preclinical stage, possibly contributing to pathology propagation and ultimately resulting in dementia.

Background: Growing evidence suggests that there may be a sex-specific biological risk for Alzheimer’s disease (AD). Individuals with autosomal dominant AD due to a mutation (E280A) in Presenilin-1 (PSEN1) are genetically determined to develop early-onset dementia and thus, have few age-related risk factors for AD that are known to vary by sex (i.e., cardiovascular disease, menopause, life expectancy). Objective: Investigate sex differences in markers of cognition and neurodegeneration in autosomal dominant AD. Methods: We conducted a retrospective study in 19 cognitively-unimpaired PSEN1 mutation carriers (age range 20–44; 11 females), 11 symptomatic carriers (age range 42–56; 8 females), and 23 matched non-carriers family members (age range 20–50; 13 females). We examined hippocampal volume ratio, CERAD Total Score, and CERAD Word List (i.e., Learning, Delayed Recall, and Recognition). Mann-Whitney U tests, Spearman correlations and regression models were conducted. Results: There were no differential associations between age, CERAD Total Score, CERAD Word List–Learning, Delayed Recall, Recognition, and hippocampal volume ratio in male and female carriers and non-carriers. Cognitively-unimpaired female carriers showed better CERAD Total scores and CERAD Word List-Learning than cognitively-unimpaired male carriers, despite having similar hippocampal volume ratios. The interaction of sex and hippocampal volume ratio did not predict cognitive performance across groups. Conclusion: Our preliminary findings suggest that cognitively-unimpaired female carriers showed a verbal memory reserve, and as disease progresses, female carriers did not exhibit a cognitive susceptibility to AD-related neurodegeneration. Future studies with larger samples of autosomal dominant AD are warranted to further understand sex differences in AD-related clinical and pathological markers.

ObjectiveTo determine whether performance on the Free and Cued Selective Reminding Test (FCSRT) is associated with PET in vivo markers of brain pathology and whether it can distinguish those who will develop dementia later in life due to autosomal-dominant Alzheimer disease (AD) from age-matched controls.MethodsTwenty-four cognitively unimpaired Presenilin-1 E280A carriers (mean age 36 years) and 28 noncarriers (mean age 37 years) underwent Pittsburg compound B-PET (amyloid), flortaucipir-PET (tau), and cognitive testing, including the FCSRT (immediate and delayed free and cued recall scores). Linear regressions were used to examine the relationships among FCSRT scores, age, mean cortical amyloid, and regional tau burden.ResultsFree and total recall scores did not differ between cognitively unimpaired mutation carriers and noncarriers. Greater age predicted lower free recall and delayed free and total recall scores in carriers. In cognitively impaired carriers, delayed free recall predicted greater amyloid burden and entorhinal tau, while worse immediate free recall scores predicted greater tau in the inferior temporal and entorhinal cortices. In turn, in all carriers, lower free and total recall scores predicted greater amyloid and regional tau pathology.ConclusionsFCSRT scores were associated with in vivo markers of AD–related pathology in cognitively unimpaired individuals genetically determined to develop dementia. Difficulties on free recall, particularly delayed recall, were evident earlier in the disease trajectory, while difficulties on cued recall were seen only as carriers neared the onset of dementia, consistent with the pathologic progression of the disease. Findings suggest that the FCSRT can be a useful measure to track disease progression in AD.

This cohort study investigates differences in cognitive functioning by sex and genetic variant status among Colombian children the autosomal dominant Alzheimer disease presenilin 1 E280A variant., Key Points Question Do children from the Colombian kindred with autosomal dominant Alzheimer disease (ADAD) differ in general cognitive functioning based on sex or genetic status? Findings In this cohort study of 1354 Colombian children (including 265 children with the presenilin 1 E280A variant), those with and without the variant did not differ on cognitive abilities. However, boys with the variant exhibited statistically significantly worse working memory performance compared with girls with the variant, as well as boys and girls without the variant. Meaning This study found that boys with the ADAD variant had increased risk of worse cognitive performance compared with girls with and without the variant, as well as boys without the variant., Importance We previously reported that children with the autosomal dominant Alzheimer disease (ADAD) presenilin 1 (PSEN1) E280A variant had early life plasma biomarker findings consistent with amyloid β overproduction. However, the cognitive functioning of children with this variant has not been characterized vs those without the variant. Objective To test whether cognitive functioning of children with and without the PSEN1 E280A variant in the same ADAD cohort differed by genetic status (ie, PSEN1 variant) and sex. Design, Setting, and Participants This cohort study was conducted among 1354 children (including 265 children with the variant) aged 6 to 16 years recruited from the Alzheimer Prevention Initiative Colombia Registry. Participants from the city of Medellín and surrounding suburban areas traveled to the University of Antioquia to undergo all procedures. Participants were administered a Spanish version of the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) to measure general cognitive functioning. Data were analyzed from July through November 2020. Main Outcomes and Measures Univariate general linear models were used to characterize differences on WISC-IV cognitive performance by genetic status, sex, and the interaction of genetic status with sex. Urbanity, socioeconomic status, and education were entered as covariates. Results Among 1354 children with ADAD (695 [51.3%] girls; mean [SD] age, 11.64 [2.64] years), there were 265 children with the variant (19.6%) and 1089 children without the variant (80.4%). Children with and without the variant did not differ by demographic variables or performance on WISC-IV indices. Irrespective of genetic status, boys had statistically significantly decreased mean scores on indices for working memory (90.27 [95% CI, 89.21-91.34] vs 92.99 [95% CI, 91.98-93.99]; mean difference = −2.72; P

The human brain is composed of functional networks that have a modular topology, where brain regions are organized into communities that form internally dense (segregated) and externally sparse (integrated) subnetworks that underlie higher-order cognitive functioning. It is hypothesized that amyloid-β and tau pathology in preclinical Alzheimer’s disease (AD) spread through functional networks, disrupting neural communication that results in cognitive dysfunction. We used high-resolution (voxel-level) graph-based network analyses to test whether in vivo amyloid-β and tau burden was associated with the segregation and integration of brain functional connections, and episodic memory, in cognitively-unimpaired Presenilin-1 E280A carriers who are expected to develop early-onset AD dementia in approximately 13 years on average. Compared to non-carriers, mutation carriers exhibited less functional segregation and integration in posterior default-mode network (DMN) regions, particularly the precuneus, and in the retrospenial cortex, which has been shown to link medial temporal regions and cortical regions of the DMN. Mutation carriers also showed greater functional segregation and integration in regions connected to the salience network, including the striatum and thalamus. Greater tau burden was associated with lower segregated and integrated functional connectivity of DMN regions, particularly the precuneus and medial prefrontal cortex. In turn, greater tau pathology was related to higher segregated and integrated functional connectivity in the retrospenial cortex, and the anterior cingulate cortex, a hub of the salience network. These findings enlighten our understanding of how AD-related pathology distinctly alters the brain’s functional architecture in the preclinical stage, possibly contributing to pathology propagation and ultimately resulting in dementia.SIGNIFICANCE STATEMENTAmyloid-β and tau pathologies in Alzheimer’s disease (AD) are hypothesized to propagate through functional networks. Research is needed to elucidate how AD-related pathologies alter the brain’s functional connections years before symptom-onset to help predict pathology accumulation and dementia risk. Using high-resolution (voxel-level) graph-based network analyses and PET imaging, we showed that greater tau burden was associated with largely dysconnectivity of posterior default-mode network brain regions, and increased connectivity of structures associated with the salience network and others that are critical for integrating information across neural systems in cognitively-unimpaired Presenilin-1 E280A carriers. Findings enlighten how amyloid-β and tau relate to distinct patterns of functional connectivity in regions that underlie memory functioning and are critical for information processing, helping predict disease progression.

Objective:Subjective Cognitive Decline (SCD) may be an early indicator of risk for Alzheimer’s disease (AD). Findings regarding sex differences in SCD are inconsistent. Studying sex differences in SCD within cognitively unimpaired individuals with autosomal-dominant AD (ADAD), who will develop dementia, may inform sex-related SCD variations in preclinical AD. We examined sex differences in SCD within cognitively unimpaired mutation carriers from the world’s largest ADAD kindred and sex differences in the relationship between SCD and memory performance.Methods:We included 310 cognitively unimpaired Presenilin-1 (PSEN-1) E280A mutation carriers (51% females) and 1998 noncarrier family members (56% females) in the study. Subjects and their study partners completed SCD questionnaires and the CERAD word list delayed recall test. ANCOVAs were conducted to examine group differences in SCD, sex, and memory performance. In carriers, partial correlations were used to examine associations between SCD and memory performance covarying for education.Results:Females in both groups had greater self-reported and study partner-reported SCD than males (allp< 0.001). In female mutation carriers, greater self-reported (p= 0.02) and study partner-reported SCD (p< 0.001) were associated with worse verbal memory. In male mutation carriers, greater self-reported (p= 0.03), but not study partner-reported SCD (p= 0.11) was associated with worse verbal memory.Conclusions:Study partner-reported SCD may be a stronger indicator of memory decline in femalesversusmales in individuals at risk for developing dementia. Future studies with independent samples and preclinical trials should consider sex differences when recruiting based on SCD criteria.

OBJECTIVE: Neuropsychologists continue to face challenges when assessing Spanish-speaking individuals due to limited availability of normative data. We developed comprehensive normative data stratified by age and education for a Spanish neuropsychological test battery used by the Grupo de Neurociencias de Antioquia (Colombia) and the Colombian Alzheimer’s Prevention Initiative Registry, which have followed large families at risk for autosomal-dominant Alzheimer’s disease (ADAD) since the 1990s. Approximately 75% of these individuals are cognitively-unimpaired and are not genetically predisposed to develop ADAD. METHODS: We conducted a retrospective study on neuropsychological evaluations from 2,673 cognitively unimpaired individuals (56% female), with ages ranging from 18 to 86 years and education from 1 to 25 years. Neuropsychological measures included the Consortium to Establish a Registry for Alzheimer’s Disease-Colombia, and other multi-domain Spanish tests. We examined associations between age, education, and sex with cognitive performance. RESULTS: Norms stratified by age and education are presented. Cognitive performance showed small associations with age and education and was unrelated to sex. CONCLUSIONS: We provided population-based norms for Spanish tests targeting multiple cognitive domains using a large Colombian sample. These normative data may be helpful for the neuropsychological characterization of Spanish speakers from Latin America in clinical and research settings.

Introduction A small percentage of Alzheimer's disease (AD) cases are caused by genetic mutations with autosomal dominant inheritance. We report a family with a novel variant in PSEN1. Methods We performed clinical and genetic evaluation of 93 related individuals from a Colombian admixed population. 31 individuals had whole-genome sequencing. Results Genetic analysis revealed a missense variant in PSEN1 (NM_000021.3: c.1247T>C p.Ile416Thr), which originated on an African haplotype and segregated with AD logarithm of the odds score of 6. Their clinical phenotype is similar to sporadic AD except for earlier age at onset: the mean age at onset for mild cognitive impairment was 47.6 years (standard deviation 5.83) and for dementia 51.6 years (standard deviation 5.03). Discussion Ile416Thr is a novel pathogenic variant that causes AD in the sixth decade of life. The history of the region that included slave importation and admixtures within a confined geographic locale represents a "mini-population bottleneck" and subsequent emergence of a rare dominant mutation.

Background Autosomal dominant Alzheimer’s disease (ADAD) is distinguished from late-onset AD by early striatal amyloid-β deposition. To determine whether striatal Pittsburgh compound B (PiB)-PET measurements of amyloid-β can help predict disease severity in ADAD, we compared relationships of striatal and neocortical PiB-PET to age, tau-PET, and memory performance in the Colombian Presenilin 1 E280A kindred. Methods Fourteen carriers (age = 28–42, Mini-Mental State Examination = 26–30) and 20 age-matched non-carriers were evaluated using PiB, flortaucipir (FTP; tau), and memory testing (CERAD Word List Learning). PiB-PET signal was measured in neocortical and striatal aggregates. FTP-PET signal was measured in entorhinal cortex. Results Compared to non-carriers, mutation carriers had age-related elevations in both neocortical and striatal PiB binding. The PiB elevation in carriers was significantly greater in the striatum than in the neocortex. In mutation carriers, PiB binding in both the neocortex and the striatum is related to entorhinal FTP; however, the association was stronger with the striatum. Only striatal PiB was associated with worse memory. Remarkably, PiB binding in the striatum, but not in the neocortex, predicted entorhinal FTP and lower memory scores after adjusting for age, indicating that striatal PiB identified the carriers with the most severe disease. Conclusions Based on these preliminary cross-sectional findings, striatal PiB-PET measurements may offer particular value in the detection and tracking of preclinical ADAD, informing a mutation carrier’s prognosis and evaluating amyloid-β-modifying ADAD treatments.

Introduction Cortical thinning is a marker of neurodegeneration in Alzheimer's disease (AD). We investigated the age‐related trajectory of cortical thickness across the lifespan (9‐59 years) in a Colombian kindred with autosomal dominant AD (ADAD). Methods Two hundred eleven participants (105 presenilin‐1 [PSEN1] E280A mutation carriers, 16 with cognitive impairment; 106 non‐carriers) underwent magnetic resonance imaging. A piecewise linear regression identified change‐points in the age‐related trajectory of cortical thickness in carriers and non‐carriers. Results Unimpaired carriers exhibited elevated cortical thickness compared to non‐carriers, and thickness more negatively correlated with age and cognition in carriers relative to non‐carriers. We found increased cortical thickness in child carriers, after which thickness steadied compared to non‐carriers prior to a rapid reduction in the decade leading up to the expected age at cognitive impairment in carriers. Discussion Findings suggest that cortical thickness may fluctuate across the ADAD lifespan, from early‐life increased thickness to atrophy proximal to clinical onset.

BackgroundNeuroimaging studies of autosomal dominant Alzheimer’s disease (ADAD) enable characterization of the trajectories of cerebral amyloid-β (Aβ) and tau accumulation in the decades prior to clinical symptom onset. Longitudinal rates of regional tau accumulation measured with positron emission tomography (PET) and their relationship with other biomarker and cognitive changes remain to be fully characterized in ADAD.MethodsFourteen ADAD mutation carriers (Presenilin-1E280A) and 15 age-matched non-carriers from the Colombian kindred underwent 2–3 sessions of Aβ (11C-Pittsburgh compound B) and tau (18F-flortaucipir) PET, structural magnetic resonance imaging, and neuropsychological evaluation over a 2–4-year follow-up period. Annualized rates of change for imaging and cognitive variables were compared between carriers and non-carriers, and relationships among baseline measurements and rates of change were assessed within carriers.ResultsLongitudinal measurements were consistent with a sequence of ADAD-related changes beginning with Aβ accumulation (16 years prior to expected symptom onset, EYO), followed by entorhinal cortex (EC) tau (9 EYO), neocortical tau (6 EYO), hippocampal atrophy (6 EYO), and cognitive decline (4 EYO). Rates of tau accumulation among carriers were most rapid in parietal neocortex (~ 9%/year). EC tau PET signal at baseline was a significant predictor of subsequent neocortical tau accumulation and cognitive decline within carriers.ConclusionsOur results are consistent with the sequence of biological changes in ADAD implied by cross-sectional studies and highlight the importance of EC tau as an early biomarker and a potential link between Aβ burden and neocortical tau accumulation in ADAD.

BACKGROUND: Cardiovascular risk factors increase the risk of developing dementia, including Alzheimer’s disease and Vascular Dementia. Yet, it has been challenging to characterize the early and disease-specific influence of cardiovascular risk factors on the clinical expression of neurodegenerative diseases. OBJECTIVE: Studying rare clinical samples with autosomal dominant mutations leading to the early onset of dementia, this study examines the effect of global cardiovascular risk on early cognitive and neuroimaging features of Alzheimer’s disease and Vascular Dementia. METHODS: We studied 85 non-demented and stroke-free individuals, including 20 subjects with Presenilin1 (PSEN1) E280A mutation leading to the early onset of Alzheimer's disease (ADAD), 20 subjects with NOTCH3 mutations leading to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and to the early onset of Vascular Dementia, and 45 non-affected family members (non-carriers). All subjects underwent clinical examination, neuropsychological evaluation, and an MRI for quantification of structural markers of cerebral small vessel disease and neurodegeneration. Global cardiovascular risk profile was estimated using the office-based Framingham Cardiovascular Risk Profile (FCRP) score. RESULTS: In presymptomatic individuals with CADASIL, a higher FCRP score was associated with a reduced hippocampal volume (B=−0.06, p

Highlights • PET evidence of cerebellar Aβ deposition in unimpaired (CU) PSEN1 E280A kindred. • Cerebellar Aβ PET SUVR began to distinguish CU carriers from non-carriers at age 34. • Cortical and cerebellar Aβ PET SUVR are positively associated in CU carriers. • Cerebellar florbetapir SUVR correlated with lower composite score in CU carriers., Background In contrast to sporadic Alzheimer’s disease, autosomal dominant Alzheimer’s disease (ADAD) is associated with greater neuropathological evidence of cerebellar amyloid plaque (Aβ) deposition. In this study, we used positron emission tomography (PET) measurements of fibrillar Aβ burden to characterize the presence and age at onset of cerebellar Aβ deposition in cognitively unimpaired (CU) Presenilin-1 (PSEN1) E280A mutation carriers from the world’s largest extended family with ADAD. Methods 18F florbetapir and 11C Pittsburgh compound B (PiB) PET data from two independent studies – API ADAD Colombia Trial (NCT01998841) and Colombia-Boston (COLBOS) longitudinal biomarker study were included. The tracers were selected independently by the respective sponsors prior to the start of each study and used exclusively throughout. Template-based cerebellar Aβ-SUVR (standard-uptake value ratios) using a known-to-be-spared pons reference region (cerebellar SUVR_pons), to a) compare 28–56-year-old CU carriers and non-carriers; b) estimate the age at which cerebellar SUVR_pons began to differ significantly in carrier and non-carrier groups; and c) characterize in carriers associations with age, cortical SUVR_pons, delayed recall memory, and API ADAD composite score. Results Florbetapir and PiB cerebellar SUVR_pons were significantly higher in carriers than non-carriers (p

Key Points Question How does lack of awareness (anosognosia) of memory impairment evolve in the Alzheimer disease (AD) trajectory? Findings In this cohort study of 2379 members of the Alzheimer’s Prevention Initiative Registry with a presenilin (PSEN1 E280A) variant for autosomal dominant AD, awareness of memory function was increased in carriers and noncarriers approximately 14 years before their estimated median age of dementia onset (49 years). In variant carriers only, awareness of memory function was reduced in the predementia stages, reaching anosognosia 6 years before dementia onset. Meaning The findings suggest that alteration of awareness of memory function in predementia stages may inform practitioners about AD progression., Importance Recent studies have suggested that unawareness, or anosognosia, of memory decline is present in predementia stages of Alzheimer disease (AD) and may serve as an early symptomatic indicator of AD. Objective To investigate the evolution of anosognosia of memory decline in individuals who carry the PSEN1 E280A variant for autosomal dominant AD compared with family members who do not carry the variant. Design, Setting, and Participants This cohort study investigated a total of 2379 members of a Colombian kindred with autosomal dominant AD who were part of the Alzheimer’s Prevention Initiative Registry. Assessments were completed at the University of Antioquia, Colombia, with data collected between January 1, 2000, and July 31, 2019. Main Outcomes and Measures Awareness of memory function was operationalized using the discrepancy between self-report and study partner report on a memory complaint scale. Linear mixed effects models were used to assess memory self-awareness over age separately in variant carriers and noncarriers. Results This study included 396 variant carriers (mean [SD] age, 32.7 [11.9] years; 200 [50.5%] female), of whom 59 (14.9%) were cognitively impaired, and 1983 cognitively unimpaired noncarriers (mean [SD] age, 33.5 [12.5] years; 1129 [56.9%] female). The variant carriers demonstrated increased awareness until the mean (SD) age of 35.0 (2.0) years and had anosognosia at approximately 43 years of age, approximately 6 years before their estimated median age of dementia onset (49 years; 95% CI, 49-51 years). Cognitively unimpaired noncarriers reported more complaints than their study partners aged 20 and 60 years (10.1 points, P, This cohort study investigates the evolution of anosognosia of memory decline in individuals with the PSEN1 E280A variant for autosomal dominant Alzheimer disease compared with family members without the variant.

IMPORTANCE: Individuals with autosomal dominant mutations for Alzheimer disease are valuable in determining biomarkers present prior to the onset of cognitive decline, improving the ability to diagnose Alzheimer disease as early as possible. Optical coherence tomography (OCT) has surfaced as a potential noninvasive technique capable of analyzing central nervous system tissues for biomarkers of Alzheimer disease. OBJECTIVE: To evaluate whether OCT can detect early retinal alterations in carriers of the presenilin 1 (PSEN1 [OMIM 104311]) E280A mutation who are cognitively unimpaired. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional imaging study conducted from July 13, 2015, to September 16, 2020, included 10 carriers of the PSEN1 E280A mutation who were cognitively unimpaired and 10 healthy noncarrier family members, all leveraged from a homogenous Colombian kindred. Statistical analysis was conducted from September 9, 2017, to September 16, 2020. MAIN OUTCOMES AND MEASURES: Mixed-effects multiple linear regression was performed to compare the thickness values of the whole retina and individual retinal layers on OCT scans between mutation carriers and noncarriers. Simple linear-effects and mixed-effects multiple linear regression models were used to assess whether age was an effect modifier for PSEN1 mutation of amyloid β levels and retinal thickness, respectively. Fundus photographs were used to compare the number of arterial and venous branch points, arterial and venous tortuosity, and fractal dimension. RESULTS: This study included 10 carriers of the PSEN1 E280A mutation who were cognitively unimpaired (7 women [70%]; mean [SD] age, 36.3 [8.1] years) and 10 healthy noncarrier family members (7 women [70%]; mean [SD] age, 36.4 [8.2] years). Compared with noncarrier controls, PSEN1 mutation carriers who were cognitively unimpaired had a generalized decrease in thickness of the whole retina as well as individual layers detected on OCT scans, with the inner nuclear layer (outer superior quadrant, β = –3.06; P = .007; outer inferior quadrant, β = –2.60; P = .02), outer plexiform layer (outer superior quadrant, β = –3.44; P = .03), and outer nuclear layer (central quadrant, β = –8.61; P = .03; inner nasal quadrant, β = –8.39; P = .04; inner temporal quadrant, β = –9.39; P = .02) showing the greatest amount of statistically significant thinning. Age was a significant effect modifier for the association between PSEN1 mutation and amyloid β levels in cortical regions (β = 0.03; P = .001) but not for the association between PSEN1 mutation and retinal thickness. No statistical difference was detected in any of the vascular parameters studied. CONCLUSIONS AND RELEVANCE: These findings suggest that OCT can detect functional and morphologic changes in the retina of carriers of familial Alzheimer disease who are cognitively unimpaired several years before clinical onset, suggesting that OCT findings and retinal vascular parameters may be biomarkers prior to the onset of cognitive decline.

Histopathological reports suggest that subregions of the thalamus, which regulates multiple physiological and cognitive processes, are not uniformly affected by Alzheimer’s disease. Despite this, structural neuroimaging studies often consider the thalamus as a single region. Identification of in vivo Alzheimer’s-dependent volumetric changes in thalamic subregions may aid the characterization of early nuclei-specific neurodegeneration in Alzheimer’s disease. Here, we leveraged access to the largest single-mutation cohort of autosomal-dominant Alzheimer’s disease to test whether cross-sectional abnormalities in subregional thalamic volumes are evident in non-demented mutation carriers (n = 31), compared to non-carriers (n = 36), and whether subregional thalamic volume is associated with age, markers of brain pathology and cognitive performance. Using automatic parcellation we examined the thalamus in six subregions (anterior, lateral, ventral, intralaminar, medial, and posterior) and their relation to age and brain pathology (amyloid and tau), as measured by PET imaging. No between-group differences were observed in the volume of the thalamic subregions. In carriers, lower volume in the medial subregion was related to increased cortical amyloid and entorhinal tau burden. These findings suggest that thalamic Alzheimer’s-related volumetric reductions are not uniform even in preclinical and prodromal stages of autosomal-dominant Alzheimer’s disease and therefore, this structure should not be considered as a single, unitary structure in Alzheimer’s disease research., Pardilla-Delgado et al. studied individuals with autosomal-dominant Alzheimer’s disease and found that lower medial and posterior thalamic subregional volumes were associated with greater amyloid and tau burden, years before clinical onset. Findings suggest that studying thalamic sub-regions could improve our understanding of the role of this structure in Alzheimer’s disease., Graphical Abstract Graphical Abstract

Background To determine whether performance on the Latin American Spanish version of the Face-Name Associative Memory Exam (LAS-FNAME) can differentiate between cognitively intact carriers of an autosomal dominant Alzheimer’s disease mutation (E280A) in Presenilin-1, who are genetically determined to develop early-onset dementia, from matched non-carriers. We also sought to examine whether LAS-FNAME performance is associated with amyloid-β and regional tau burden in mutation carriers. Methods A total of 35 cognitively intact mutation carriers (age range 26–41), 19 symptomatic carriers, and 48 matched non-carriers (age range 27–44) completed a neuropsychological assessment including the LAS-FNAME. A subset of participants (31 carriers [12 symptomatic] and 35 non-carriers) traveled from Colombia to Boston to undergo positron emission tomography (PET) using Pittsburgh compound B to measure mean cortical amyloid-β and flortaucipir for regional tau. ANOVA analyses and Spearman correlations were used to examine group differences and relationships among LAS-FNAME performance and amyloid-β and tau accumulation. Results Compared to non-carriers, cognitively intact mutation carriers had lower scores on the LAS-FNAME Total Scores (p = .040). Across all carriers (including symptomatic carriers), higher levels of amyloid-β (r = − .436, p = .018) and regional tau in the entorhinal (r = − .394, p = .031) and inferior temporal cortex (r = − .563, p = .001) were associated with lower LAS-FNAME Total Scores. Conclusions Performance on the LAS-FNAME differentiated between cognitively intact mutation carriers from non-carriers and was associated with greater amyloid and tau burden when examining all carriers. Findings suggest that the LAS-FNAME is sensitive to early clinical and pathological changes and can potentially help track disease progression in Spanish-speaking individuals.

OBJECTIVE: Visual memory (ViM) declines early in Alzheimer’s disease (AD). However, it is unclear whether ViM impairment is evident in the preclinical stage and relate to markers of AD pathology. We examined the relationship between ViM performance and in-vivo markers of brain pathology in individuals with autosomal dominant AD (ADAD). METHODS: Forty-five cognitively unimpaired individuals from a Colombian kindred with the Presenilin 1 (PSEN1) E280A ADAD mutation (nineteen carriers and twenty-six non-carriers) completed the Rey-Osterrieth complex figure immediate recall test, a measure of ViM. Cortical amyloid burden and regional tau deposition in the entorhinal cortex (EC) and inferior temporal cortex (IT) were measured using (11)C-Pittsburgh compound B positron emission tomography (PET) and (11)F-Flortaucipir PET, respectively. RESULTS: Cognitively unimpaired carriers and non-carriers did not differ on ViM performance. Compared to non-carriers, unimpaired mutation carriers had higher levels of cortical amyloid and regional tau in both the EC and IT. In cognitively unimpaired carriers, greater cortical amyloid burden, higher levels of regional tau, and greater age were associated with worse ViM performance. Only a moderate correlation between regional tau and ViM performance remained after adjusting for verbal memory scores. None of these correlations were observed in non-carriers. CONCLUSIONS: Results suggest that AD pathology and greater age are associated with worse ViM performance in ADAD before the onset of clinical symptoms. Further investigation with larger samples and longitudinal follow-up is needed to examine the utility of ViM measures for identifying individuals at high risk of developing dementia later in life.

Background Over the past decade, visual short-term memory (VSTM) binding tests have been shown to be one of the most sensitive behavioral indicators of Alzheimer’s disease (AD), especially when they require the binding of multiple features (e.g., color and shape). Recently, it has become possible to directly measure amyloid and tau levels in vivo via positron emission tomography (PET). To this point, these behavioral and neurochemical markers have not been compared in humans with AD or at risk for it. Methods In a cross-sectional study, we compared VSTM performance to tau and amyloid concentrations, measured by PET, in individuals certain to develop AD by virtue of their inheritance of the presenilin-1 E280A mutation. These included 21 clinically unimpaired subjects and 7 subjects with early mild cognitive impairment (MCI), as well as 30 family members who were not carriers of the mutation. Results We found that VSTM performance correlated strongly with tau in entorhinal cortex and inferior temporal lobe, and also with amyloid when examining asymptomatic carriers only. The condition requiring binding was not preferentially linked to tau—in fact, the non-binding “shape only” condition showed a stronger relationship. Conclusions The results confirm VSTM’s status as an early marker of AD pathology and raise interesting questions as to the course of binding-specific versus non-binding aspects of VSTM in early AD.

Neurofilament light chain (NfL) is a promising biomarker of active axonal injury and neuronal degeneration. We aimed to characterise cross-sectional and longitudinal plasma NfL measurements and determine the age at which NfL concentrations begin to differentiate between carriers of the presenilin 1 (PSEN1) E280A (Glu280Ala) mutation and age-matched non-carriers from the Colombian autosomal dominant Alzheimer's disease kindred.In this cross-sectional and longitudinal cohort study, members of the familial Alzheimer's disease Colombian kindred aged 8-75 years with no other neurological or health conditions were recruited from the Alzheimer's Prevention Initiative Registry at the University of Antioquia (Medellín, Colombia) between Aug 1, 1995, and Dec 15, 2018. We used a single molecule array immunoassay and log-transformed data to examine the relationship between plasma NfL concentrations and age, and establish the earliest age at which NfL concentrations begin to diverge between mutation carriers and non-carriers.We enrolled a cohort of 1070 PSEN1 E280A mutation carriers and 1074 non-carriers with baseline assessments; of these participants, longitudinal measures (with a mean follow-up of 6 years) were available for 242 mutation carriers and 262 non-carriers. Plasma NfL measurements increased with age in both groups (p0·0001), and began to differentiate carriers from non-carriers when aged 22 years (22 years before the estimated median age at mild cognitive impairment onset of 44 years), although the ability of plasma NfL to discriminate between carriers and non-carriers only reached high sensitivity close to the age of clinical onset.Our findings further support the promise of plasma NfL as a biomarker of active neurodegeneration in the detection and tracking of Alzheimer's disease and the evaluation of disease-modifying therapies.National Institute on Aging, National Institute of Neurological Disorders and Stroke, Banner Alzheimer's Foundation, COLCIENCIAS, the Torsten Söderberg Foundation, the Swedish Research Council, the Swedish Alzheimer Foundation, the Swedish Brain Foundation, and the Swedish state under the ALF-agreement.

OBJECTIVE: The Face-Name Associative Memory Exam (FNAME) has been used to detect subtle cognitive changes in clinically normal older adults at increased risk for Alzheimer’s disease. FNAME assesses learning and delayed recall for face-name pairs. The aim of this study is to introduce a Latin American Spanish version of the FNAME (LAS-FNAME), examine its psychometric properties, and provide preliminary normative data in a sample of clinically normal, Spanish-speaking individuals from Antioquia, Colombia. METHOD: 59 clinically normal individuals (71% females) were recruited by the Grupo de Neurociencias in Antioquia (Colombia). Age ranged from 27 to 82 years ( M=50.31, SD=15.32) and years of education ranged from 2 to 17 years (M=9.02, SD=4.11). All participants completed the LAS-FNAME and a brief neuropsychological evaluation. We examined associations between age, education, and sex and performance on the LAS-FNAME. Internal consistency, convergent and discriminant validity were also assessed. Test-restest reliability was computed for a subset of participants (n = 32). RESULTS: LAS-FNAME exhibited moderate convergent validity with other memory measures (Free and Cued Selective Reminding Scale, r(s)=.465, p65) and low and high educational attainment (≤8 and >8 years of education, respectively). CONCLUSIONS: The LAS-FNAME is a valid and reliable measure to assess memory in clinically normal, Spanish-speaking individuals from Colombia for clinical and research purposes.

Background There is a need to find cognitive markers that can help identify individuals at risk for Alzheimer's disease (AD), and that can be used to reliably measure cognitive decline. Objective We tested whether a theoretically driven three-factor structure would characterize cognitive functioning in individuals who are genetically-determined to develop AD due to a mutation in Presenilin-1 (PSEN1) gene. We also examined whether these factors could distinguish cognitively unimpaired PSEN1 mutation carriers from age-matched non-carrier family members. Methods 1,395 cognitively unimpaired members of a Colombian kindred with the PSEN1 E280A mutation were included in the study. A confirmatory factor analysis examined the fit of the three-factor model comprising episodic memory (MMSE memory recall, CERAD-COL Word list recall, and Constructional praxis recall), executive function (Phonemic fluency and WCST perseverative errors), and psychomotor processing speed (TMT-A and WAIS-III Digit Symbol). Results The three-factor model provided an excellent fit for all participants (p = 0.24; RMSEA = 0.01). Further, the episodic memory (p = 0.0004, d = 0.25) and executive functioning (p = 0.001, d = 0.18) factors distinguished cognitively unimpaired carriers from non-carriers. The episodic memory factor provided the earliest indication of preclinical cognitive decline at 35 years of age, nine years before individuals' estimated age of clinical onset. Conclusions The three theoretically derived cognitive factors provide a reliable measure of cognition and may be useful for the early detection of AD, as well as for measuring disease progression. However, longitudinal studies are needed to confirm that these factors can be used to track the progression of cognitive decline in preclinical AD.

Introduction Although the social and economic consequences of Colombian internal conflicts mainly affected the civilian population, they also had other implications. The ex-combatants, the other side of the conflict, have been the subject of many studies that question their personality structures and antisocial features. Results suggest that ex-combatants usually have characteristics of an antisocial personality disorder (ASPD) that is related with their behaviour. Methods Quantitative EEG (qEEG) was used to evaluate differences in cortical activity patterns between an ex-combatants group and a control group. The Psychopathy Checklist-Revised (PCL-R) was used to assess the presence of ASPD in the ex-combatants group, as well as the Diagnostic Interview for Genetic Studies (DIGS) for other mental disorders classified in the DCI-10. Results There are significant differences in psychopathy levels between groups, as well as in alpha-2 and beta waves, especially in left temporal and frontal areas for alpha-2 waves and left temporal-central regions for beta waves. Conclusions qEEG measurements allow spectral resting potential to be differentiated between groups that are related with features typically involved in antisocial personality disorder, and to correlate them with patterns in the questionnaires and clinical interview.

Resumen Introduccion El conflicto armado colombiano, ademas de secuelas sociales y economicas en la poblacion civil, ha implicado otras consecuencias. Los excombatientes, como la otra cara del conflicto, han sido objeto de interrogacion sobre su estructura de personalidad y predisposicion a conductas violentas. Se ha encontrado en parte de la poblacion asociada al conflicto armado rasgos caracteristicos del trastorno de personalidad antisocial (TPA) que se relacionarian con los comportamientos en contra de las convenciones sociales. Metodos Mediante registros electrocardiograficos cuantitativos (qEEG), se evaluaron las diferencias en los patrones de actividad cortical entre un grupo de excombatientes, algunos de ellos con diagnostico de TPA, y un grupo de control ajeno al conflicto armado y sin alteraciones psiquiatricas. Se empleo la Lista de Chequeo de Psicopatia Revisada (PCL-R) para determinar la presencia de criterios diagnosticos de TPA, asi como la entrevista diagnostica para estudios geneticos (DIGS) para clasificar la presencia de otros trastornos mentales incluidos en el CIE-10. Resultados Se encontraron diferencias significativas en los niveles de psicopatia evaluados mediante la PCL-R. Con respecto al analisis de la potencia espectral, se observaron diferencias entre grupos en las ondas alfa-2 y beta, en regiones frontal y temporal izquierda y temporocentral izquierda respectivamente. Conclusiones La tecnica de qEEG permite evidenciar las diferencias entre grupos en el potencial espectral en reposo, las cuales se relacionan con comportamientos desadaptativos caracteristicos del TPA.

Background Presenilin-1 (PSEN1) mutations are the most common cause of familial early onset Alzheimer's disease (AD). The PSEN1 E280A (E280A) mutation has an autosomal dominant inheritance and is involved in the production of amyloid-β. The largest family group of carriers with E280A mutation is found in Antioquia, Colombia. The study of mutation carriers provides a unique opportunity to identify brain changes in stages previous to AD. Electroencephalography (EEG) is a low cost and minimally invasiveness technique that enables the following of brain changes in AD. Objective To examine how previous reported differences in EEG for Theta and Alpha-2 rhythms in E280A subjects are related to specific regions in cortex and could be tracked across different ages. Methods EEG signals were acquired during resting state from non-carriers and carriers, asymptomatic and symptomatic subjects from E280A kindred from Antioquia, Colombia. Independent component analysis (ICA) and inverse solution methods were used to locate brain regions related to differences in Theta and Alpha-2 bands. Results ICA identified two components, mainly related to the Precuneus, where the differences in Theta and Alpha-2 exist simultaneously at asymptomatic and symptomatic stages. When the ratio between Theta and Alpha-2 is used, significant correlations exist with age and a composite cognitive scale. Conclusion Theta and Alpha-2 rhythms are altered in E280A subjects. The alterations are possible to track at Precuneus regions using EEG, ICA, and inverse solution methods.