Early-onset Alzheimer's Disease Patients Research Articles

Targeting the cholinergic anti-inflammatory pathway for type 2 diabetes prevention: A retrospective cohort study.

Chronic inflammation is a key factor in type 2 diabetes mellitus (T2DM) development. The cholinergic anti-inflammatory pathway (CAP) reduces inflammation by activating α7 nicotinic acetylcholine receptors (α7nAChRs) on macrophages, suppressing proinflammatory cytokines. Acetylcholinesterase inhibitors (AChEis), primarily used for Alzheimer's disease (AD), may exert anti-inflammatory effects through the CAP. One AChEi, galantamine, also directly agonizes α7nAChRs, potentially enhancing its anti-inflammatory properties. This study aimed to investigate the association between AChEi use, particularly galantamine, and T2DM risk in AD patients. We conducted a retrospective analysis of Veterans Health Administration (VA) data, examining early- and late-onset AD patients receiving galantamine or other AD medications. Propensity score matching was used to balance groups and minimize confounding. Cox proportional hazard models assessed T2DM risk for galantamine, other AChEis and memantine. A total of 40 065 AD patients were included in the study. Among early-onset AD patients, galantamine use significantly reduced T2DM risk (hazard ratio [HR] = 0.80, 95% confidence interval [CI]: 0.66-0.98). Memantine also showed a protective effect (HR = 0.82, 95% CI: 0.69-1) in this group. Neither galantamine nor memantine influenced T2DM risk in late-onset AD. Other AD medications showed no association with T2DM risk. Galantamine use was associated with a lower risk of T2DM in early-onset AD patients, potentially due to enhanced anti-inflammatory effects through both AChE inhibition and direct α7nAChR agonism. Memantine also demonstrated a protective effect. These findings suggest potential new applications for existing AD medications in T2DM prevention, particularly in early-onset AD patients. Further research, including randomized controlled trials with diverse populations, is needed to confirm these results and the underlying mechanisms.

Genotyping Apolipoprotein E (APOE) Isoforms with Sequence-Specific-Primer (SSP)-PCR in Early‑Onset Alzheimer’s Disease Patients: A Rapid and Revised Methodology

Alzheimer's disease (AD) is a neurodegenerative disorder that causes progressive damage to brain cells, leading to impairment in cognitive functions. The Apolipoprotein E (APOE) variants play a significant role in the genetic basis of AD, especially late-onset AD (LOAD), and increase the disease risk at an earlier age. Although controversial, some studies reveal the association between APOE genotype and early-onset AD (EOAD) regardless of family history. Therefore, diagnostic laboratories widely perform routine tests to determine the APOE genotype. In the present study, we implemented a revised methodology for the Sequence-Specific-Primer-PCR (SSP-PCR) test for rapid APOE genotyping in 67 EOAD patients. Then, the findings were validated using automatic sequencing with newly designed primers for the related region of the APOE. We state clearly that the applicability of the SSP-PCR method was improved when the primer concentrations of control genes were increased 2-fold, as we reported. All data obtained from SSP-PCR were consistent with Sanger sequencing confirmations. Based on the genotyping results, the four different APOE genotypes were detected: E2/E4, E3/E3, E3/E4, and E4/E4. The frequencies were 1.5% (n=1) for E2/E4, 76.1% (n=51) for E3/E3, 16.4% (n=11) for E3/E4, and 6% (n=4) for E4/E4. In the study group, 23.9% (n=16) of the patients had homozygous or heterozygous APOE E4. However, we detected no significant association between the clinical features and the APOE genotype. As a result, this method is reliable, cost-effective, and rapid for performing genotyping analysis of the APOE for routine tests and research studies with larger EOAD cohorts.

MTHFR Polymorphisms and Plasma Homocysteine in Early-Onset Alzheimer's Disease: A Case-Control Study

Background: Early-onset Alzheimer's disease (EOAD) constitutes 1-2% of all Alzheimer's cases, presenting with poorer prognosis, progressive symptoms, and reduced life expectancy compared to late-onset Alzheimer’s, thereby increasing socioeconomic burden. Elevated plasma homocysteine levels due to MTHFR gene polymorphisms are implicated in Alzheimer's etiology. The present study aims to explore the association between MTHFR gene polymorphisms in Sudanese population. Methods: Seventy-three EOAD patients were assessed for MTHFR C677T and A1298C polymorphisms, alongside plasma homocysteine levels. Results: Significant associations were observed between CT and TT alleles, elevated plasma homocysteine levels, and EOAD. Conclusion: MTHFR C677T polymorphism was associated in EOAD in Sudanese population. Elevated plasma homocysteine levels might frame this association and potentially contribute to the disease onset before the age of 65.

Diverging Relationships among Amyloid, Tau, and Brain Atrophy in Early-Onset and Late-Onset Alzheimer's Disease.

Alzheimer's disease (AD) dementia may not be a single disease entity. Early-onset AD (EOAD) and late-onset AD (LOAD) have been united under the same eponym of AD until now, but disentangling the heterogeneity according to the age of sonset has been a major tenet in the field of AD research. Ninety-nine patients with AD (EOAD, n=54; LOAD, n=45) and 66 cognitively normal controls completed both [18F]THK5351 and [18F]flutemetamol (FLUTE) positron emission tomography scans along with structural magnetic resonance imaging and detailed neuropsychological tests. EOAD patients had higher THK retention in the precuneus, parietal, and frontal lobe, while LOAD patients had higher THK retention in the medial temporal lobe. Intravoxel correlation analyses revealed that EOAD presented narrower territory of local FLUTE-THK correlation, while LOAD presented broader territory of correlation extending to overall parieto-occipito-temporal regions. EOAD patients had broader brain areas which showed significant negative correlations between cortical thickness and THK retention, whereas in LOAD, only limited brain areas showed significant correlation with THK retention. In EOAD, most of the cognitive test results were correlated with THK retention. However, a few cognitive test results were correlated with THK retention in LOAD. LOAD seemed to show gradual increase in tau and amyloid, and those two pathologies have association to each other. On the other hand, in EOAD, tau and amyloid may develop more abruptly and independently. These findings suggest LOAD and EOAD may have different courses of pathomechanism.

Choriocapillaris reduction accurately discriminates against early-onset Alzheimer's disease.

This study addresses the urgent need for non-invasive early-onset Alzheimer's disease (EOAD) prediction. Using optical coherence tomography angiography (OCTA), we present a choriocapillaris model sensitive to EOAD, correlating with serum biomarkers. Eighty-four EOAD patients and 73 controls were assigned to swept-source OCTA (SS-OCTA) or the spectral domain OCTA (SD-OCTA) cohorts. Our hypothesis on choriocapillaris predictive potential in EOAD was tested and validated in these two cohorts. Both cohorts revealed diminished choriocapillaris signals, demonstrating the highest discriminatory capability (area under the receiver operating characteristic curve: SS-OCTA 0.913, SD-OCTA 0.991; P<0.001). A sparser SS-OCTA choriocapillaris correlated with increased serum amyloid beta (Aβ)42, Aβ42/40, and phosphorylated tau (p-tau)181 levels (all P<0.05). Apolipoprotein E status did not affect choriocapillaris measurement. The choriocapillaris, observed in both cohorts, proves sensitive to EOAD diagnosis, and correlates with serum Aβ and p-tau181 levels, suggesting its potential as a diagnostic tool for identifying and tracking microvascular changes in EOAD. Optical coherence tomography angiography may be applied for non-invasive screening of Alzheimer's disease (AD). Choriocapillaris demonstrates high sensitivity and specificity for early-onset AD diagnosis. Microvascular dynamics abnormalities are associated with AD.

Generation and characterization of an iPS cell line (PUMCi006-A) from skin fibroblasts of a patient with an M239T mutation in PSEN2 gene

Presenilin-2 (PSEN2) mutation is one of the pathogenic factors of autosomal dominant early-onset Alzheimer's disease (EOAD). We generated a human induced pluripotent stem cell (iPSC) line from fibroblasts of an EOAD patient carrying PSEN2 mutation (c.716 T > C) utilizing Sendai reprogramming kit. The resulting iPSC line carried patient-specific point mutation, exhibited typical iPSC morphology, retained a normal karyotype, expressed pluripotency markers, and could form embryoid bodies. Established iPSC line serve as valuable resource for EOAD disease pathogenesis modelling and drug screening.

Correlation between serum biomarkers, brain volume, and retinal neuronal loss in early-onset Alzheimer's disease.

To compare the peripapillary retinal nerve fiber layer (pRNFL), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) thickness measurement in early-onset Alzheimer's disease (EOAD) and controls using spectral domain optical coherence tomography (SD-OCT). We also assessed the relationship between SD-OCT measurements and cognitive measures, serum biomarkers for Alzheimer's disease (AD), and cerebral microstructural volume. pRNFL, RNFL, and GCC thicknesses were measured in 43 EOAD and 42 controls using SD-OCT. Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) were used to assess cognitive status, magnetic resonance imaging (MRI) tool was used to quantify cerebral microstructural volume, and serum biomarkers were quantified from peripheral blood. EOAD patients had thinner pRNFL (P < 0.001), RNFL (P = 0.008), and GCC (P = 0.018) thicknesses compared to controls after adjusting for multiple factors. pRNFL thickness correlated (P = 0.016) with serum t-tau level. Serum Aβ42 (P < 0.05) concentration correlated with RNFL thickness. Importantly, occipital lobe volume (P = 0.010) correlated with GCC thicknesses in EOAD patients. Our findings suggest that retinal thickness may be useful markers for assessing neurodegenerative processin EOAD.

Carvedilol suppresses ryanodine receptor-dependent Ca2+ bursts in human neurons bearing PSEN1 variants found in early onset Alzheimer's disease.

Seizures are increasingly being recognized as the hallmark of Alzheimer's disease (AD). Neuronal hyperactivity can be a consequence of neuronal damage caused by abnormal amyloid β (Aß) depositions. However, it can also be a cell-autonomous phenomenon causing AD by Aß-independent mechanisms. Various studies using animal models have shown that Ca2+ is released from the endoplasmic reticulum (ER) via type 1 inositol triphosphate receptors (InsP3R1s) and ryanodine receptors (RyRs). To investigate which is the main pathophysiological mechanism in human neurons, we measured Ca2+ signaling in neural cells derived from three early-onset AD patients harboring Presenilin-1 variants (PSEN1 p.A246E, p.L286V, and p.M146L). Of these, it has been reported that PSEN1 p.A246E and p.L286V did not produce a significant amount of abnormal Aß. We found all PSEN1-mutant neurons, but not wild-type, caused abnormal Ca2+-bursts in a manner dependent on the calcium channel, Ryanodine Receptor 2 (RyR2). Indeed, carvedilol, an RyR2 inhibitor, and VK-II-86, an analog of carvedilol without the β-blocking effects, sufficiently eliminated the abnormal Ca2+ bursts. In contrast, Dantrolene, an inhibitor of RyR1 and RyR3, and Xestospongin c, an IP3R inhibitor, did not attenuate the Ca2+-bursts. The Western blotting showed that RyR2 expression was not affected by PSEN1 p.A246E, suggesting that the variant may activate the RyR2. The RNA-Seq data revealed that ER-stress responsive genes were increased, and mitochondrial Ca2+-transporter genes were decreased in PSEN1A246E cells compared to the WT neurons. Thus, we propose that aberrant Ca2+ signaling is a key link between human pathogenic PSEN1 variants and cell-intrinsic hyperactivity prior to deposition of abnormal Aß, offering prospects for the development of targeted prevention strategies for at-risk individuals.

Clinical Manifestations.

Perturbations in immune pathways are strongly associated with Alzheimer's disease. A positive association between autoimmune diseases and frontotemporal dementia has been reported. We explored whether early onset Alzheimer's disease (EOAD) would associate with autoimmune diseases. We compared 313 patients with EOAD from the Mayo Clinic Florida, Alzheimer's Disease Research Center (ADRC) Registry with matched cognitively normal controls (NC) based on age (+/- 2 years) and gender at 1:2 ratio. NC were derived from Mayo Clinic Biobank Project, Rochester (N = 313) and the Mayo Clinic Study of Aging (N = 313). Data abstraction was performed by trained statisticians using ICD 9&10 codes corresponding to 40 specified autoimmune diseases and/or documentation of specified immunomodulatory treatment. Data was also abstracted via retrospective record review. We further reviewed clinical records from EOAD patients with neuropathologically confirmed Alzheimer's disease patients enrolled in the ADRC (n = 10). Each autoimmune disease type was compared between cases and controls using Fisher's exact test. All tests were two-sided with alpha level set at 0.05 for statistical significance. Continuous variables were summarized as median (range) while categorical variables were reported as frequency (percentage). The prevalence of autoimmune disease in the general population was based off Hayter & Cook, 2012 and Roberts & Erdei, 2020. All data abstraction was done blinded to the clinical diagnosis and baseline demographics. Autoimmune disease history was abstracted from 949 patient records (313 EOAD, 10 pathologically-confirmed EOAD, 626 NCI). The median age was 57 years-old. (EOAD range 28,65 yrs.; NC 30,66 yrs.). Autoimmune thyroiditis (p = 0.0008), ulcerative colitis (p = 0.011, psoriasis (<0.0001), rheumatoid arthritis (p = 0.0005), and Raynaud's syndrome (p = 0.0021) were less prevalent in patients with EOAD compared to NC. Furthermore, patients with EOAD had a lower prevalence of immune mediated hematologic disorders. Patients with EOAD have a lower prevalence of autoimmune diseases than NC. Immune activation identified in early onset AD patients may be unrelated to autoimmunity. Findings should be explored in late onset AD patients.

The rs‐gamma connectivity alterations related to the atrophy pattern and CSF p‐tau in early‐onset AD

AbstractBackgroundAmong the other frequencies, the gamma frequency has received the least attention in the study of Alzheimer’s disease (AD). Previous studies point to association between amyloid accumulation and gamma alterations, suggesting that gamma activity may serve as a potential biomarker for the pathophysiology of AD. The goal of the current study is to examine changes in resting‐state (rs) gamma activity in patients with CSF‐proven early‐onset AD (EOAD) and their relationship to structural pathology associated with the disease.MethodDrug‐naive CSF‐proven EOAD patients [mean age: 57.92 (4.35) years] and age‐, gender, and education‐matched healthy controls (HC) [mean age: 57.58 (4.01) years] were included. Gamma imaginary part of coherency (ICoh) was measured in total gamma (30‐48 Hz), gamma‐1 (30‐35 Hz), gamma‐2 (35‐40 Hz), and gamma‐3 (40‐48 Hz) frequencies. Gray matter volumes compared between groups. The rsEEG gamma activity was used for discriminant analysis. The relationships between rsEEG, MRI, and CSF p‐tau measurements were investigated.ResultIn the EOAD group, gray matter volume in temporal, parietal, and occipital areas were decreased by over 20%. We discovered that the volume of frontal and neighboring regions, that were intact in this patient group, was negatively correlated with F8‐TP8 and F4‐C4 ICoh of sub‐gamma bands. On the contrary, the volume of temporal and parietal regions where the atrophy was prominent, was positively correlated with P8‐O2 and C3‐O1 ICoh of sub‐gamma bands. In the EOAD, executive function and F7‐TP7, P3‐O1 sub‐gamma bands were negatively correlated.Regarding CSF, p‐Tau and C3‐C4 gamma‐1 showed strong positive correlation (r = 0.615). Lastly, a set of gamma ICoh measurements displayed a correct classification rate of 83% between groups.ConclusionGamma coherence follows pair‐specific alterations related to atrophy pattern in EOAD. The gamma connectivity becomes greater where atrophy is increased and when CSF p‐tau is higher in EOAD. This study establishes the significance of sub‐gamma oscillations as a non‐invasive biomarker candidate with achieving an 83% correct classification rate between groups.

High burdens of phosphorylated tau protein and distinct precuneus atrophy in sporadic early-onset Alzheimer’s disease

Early-onset Alzheimer’s disease (EOAD) is a rare devastating subclassification of Alzheimer’s disease (AD). EOAD affects individuals <65 years old, and accounts for 5%–10% of all AD cases. Previous studies on EOAD primarily focused on familial forms, whereas research on sporadic EOAD (sEOAD), which represents 85%–90% of EOAD cases, is limited. In this prospective cohort study, participants were recruited between 2018 and 2023 and included patients with sEOAD (n = 110), late-onset AD (LOAD, n = 89), young controls (YC, n = 50), and older controls (OC, n = 25). All AD patients fulfilled the diagnostic criteria based on biomarker evidence. Familial EOAD patients or non-AD dementia patients were excluded. Single molecule array technology was used to measure fluid biomarkers, including cerebrospinal fluid (CSF) and plasma amyloid beta (Aβ) 40, Aβ42, phosphorylated tau (P-tau) 181, total tau (T-tau), serum neurofilament light chain and glial fibrillary acidic protein (GFAP). Patients with sEOAD exhibited more severe executive function impairment and bilateral precuneus atrophy (P < 0.05, family-wise error corrected) than patients with LOAD. Patients with sEOAD showed elevated CSF and plasma P-tau181 levels (154.0 ± 81.2 pg/mL, P = 0.002; and 6.1 ± 2.3 pg/mL, P = 0.046). Moreover, precuneus atrophy was significantly correlated with serum GFAP levels in sEOAD (P < 0.001). Serum GFAP levels (area under the curve (AUC) = 96.0%, cutoff value = 154.3 pg/mL) displayed excellent diagnostic value in distinguishing sEOAD patients from the control group. These preliminary findings highlight the crucial role of tau protein phosphorylation in the pathogenesis and progression of sEOAD.

The Sporadic Early-onset Alzheimer's Disease Signature Of Atrophy: Preliminary Findings From The Longitudinal Early-onset Alzheimer's Disease Study (LEADS) Cohort.

Magnetic resonance imaging (MRI) research has advanced our understanding of neurodegeneration in sporadic early-onset Alzheimer's disease (EOAD) but studies include small samples, mostly amnestic EOAD, and have not focused on developing an MRI biomarker. We analyzed MRI scans to define the sporadic EOAD-signature atrophy in a small sample (n=25) of Massachusetts General Hospital (MGH) EOAD patients, investigated its reproducibility in the large longitudinal early-onset Alzheimer's disease study (LEADS) sample (n=211), and investigated the relationship of the magnitude of atrophy with cognitive impairment. The EOAD-signature atrophy was replicated across the two cohorts, with prominent atrophy in the caudal lateral temporal cortex, inferior parietal lobule, and posterior cingulate and precuneus cortices, and with relative sparing of the medial temporal lobe. The magnitude of EOAD-signature atrophy was associated with the severity of cognitive impairment. The EOAD-signature atrophy is a reliable and clinically valid biomarker of AD-related neurodegeneration that could be used in clinical trials for EOAD. We developed an early-onset Alzheimer's disease (EOAD)-signature of atrophy based on magnetic resonance imaging (MRI) scans. EOAD signature was robustly reproducible across two independent patient cohorts. EOAD signature included prominent atrophy in parietal and posterior temporal cortex. The EOAD-signature atrophy was associated with the severity of cognitive impairment. EOAD signature is a reliable and clinically valid biomarker of neurodegeneration.

Early-onset Alzheimer's disease explained by polygenic risk of late-onset disease?

Early-onset Alzheimer's disease (AD) is highly heritable, yet only 10% of cases are associated with known pathogenic mutations. For early-onset AD patients without an identified autosomal dominant cause, we hypothesized that their early-onset disease reflects further enrichment of the common risk-conferring single nucleotide polymorphisms associated with late-onset AD. We applied a previously validated polygenic hazard score for late-onset AD to 193 consecutive patients diagnosed at our tertiary dementia referral center with symptomatic early-onset AD. For comparison, we included 179 participants with late-onset AD and 70 healthy controls. Polygenic hazard scores were similar in early- versus late-onset AD. The polygenic hazard score was not associated with age-of-onset or disease biomarkers within early-onset AD. Early-onset AD does not represent an extreme enrichment of the common single nucleotide polymorphisms associated with late-onset AD. Further exploration of novel genetic risk factors of this highly heritable disease is warranted.Highlights: There is a unique genetic architecture of early- versus late-onset Alzheimer's disease (AD).Late-onset AD polygenic risk is not an explanation for early-onset AD.Polygenic risk of late-onset AD does not predict early-onset AD biology.Unique genetic architecture of early- versus late-onset AD parallels AD heterogeneity.

Cross‐species evidence of differential expression of S100A6 and SLC11A1 in the hippocampus of Alzheimer’s disease patients and mouse models

AbstractBackgroundThe evaluation of similarities and differences between mouse models and human Alzheimer’s disease (AD) provides invaluable insights on disease pathophysiology. We compared hippocampal transcriptomic profiles of human late‐onset AD (LOAD) and early‐onset AD (EOAD) individuals with three mouse models (hAβ‐KI, APP/PS1 and 5xFAD) in an exploratory analysis. Afterwards, we validated the intersection of genes consistently altered in all groups using hippocampal tissue from APP/PS1 mice, and EOAD and LOAD patients.MethodsFive publicly available human AD/cognitively unimpaired (CU) transcriptomic profiles were collected from GEO (https://www.ncbi.nlm.nih.gov/geo/), merged and submitted to differential expression analysis (DEA) using R. APP/PS1 mouse model RNAseq data from two datasets (GSE149661 and GSE145907) were also collected. Finally, RNAseq data of 5xFAD and hAβ‐KI mouse models were obtained from AMP‐AD Knowledge Portal (https://www.synapse.org/) using synapser and synapserutils packages. All animal models were also submitted to DEA. Validation of selected genes was performed by qRT‐PCR. Target mRNA levels were normalized using β‐actin as a housekeeper gene. The results were expressed relative to wild‐type (WT) animals or CU controls using the 2−ΔΔCt method.ResultsDEA identified 1164, 3261 and 1782 differentially expressed genes (DEGs) for the comparisons between hAβ‐KI, 5xFAD and APP/PS1 mutants versus WT controls, respectively. hAβ‐KI, APP/PS1, and 5xFAD mice exhibited more DEGs in common with LOAD than with EOAD patients. Interestingly, APP/PS1 and 5xFAD mice also presented more DEGs in common with LOAD than with EOAD patients. However, 5xFAD showed significantly higher DEGs intersection with EOAD than with hAβ‐KI and APP/PS1. Additionally, we identified S100A6, C1QB, SST, CD14, CD33, SLC11A1 and KCNK1 genes altered in both EOAD and LOAD as well as the three mouse models evaluated. qRT‐PCR analysis of these genes in EOAD, LOAD and APP/PS1 model revealed S100A6 and SLC11A1 consistently altered in human pathology and mouse model.ConclusionAnimal models seek to better simulate AD pathology, making the evaluation of their molecular overlap with human disease greatly important. S100A6, a calcium‐binding protein modulating several biological activities, and SLC11A1, a metal transporter associated with inflammatory processes, were consistently altered in our transcriptomics exploratory analyses and experimental validation, making them promising targets for further investigation.

Octapeptide repeat alteration mutations of the prion protein gene in clinically diagnosed Alzheimer's disease and frontotemporal dementia.

Studies focusing on octapeptide repeat alteration mutations in PRNP in Alzheimer's disease (AD) and frontotemporal dementia (FTD) cohorts have been rare. We aim to screen sporadic AD and FTD patients with unknown etiology for the octapeptide repeat insertions and deletions in PRNP. Two hundred and six individuals were screened for alterations to the repeat region in the PRNP gene, including 146 sporadic AD and 60 sporadic FTD patients. Our study showed a 1.5% (3/206) occurrence of the octapeptide repeat alteration mutations in PRNP in a Chinese cohort of sporadic dementia. One late-onset FTD patient and one early-onset AD patient each had a two-octapeptide repeat deletion in PRNP, while one early-onset AD patient had a five-octapeptide repeat insertion mutation. PRNP octapeptide repeat alteration mutations are present in sporadic AD and FTD patients. The genetic investigation for PRNP octapeptide repeat alteration mutations in sporadic dementia patients should be carried out in future clinical studies.

Ethnic Disparities in Clinical Presentation of Patients with Early-Onset Alzheimer’s Disease (P14-6.002)

<h3>Objective:</h3> N/A <h3>Background:</h3> Early-onset Alzheimer’s Disease (EOAD) affects patients younger than age 65 and may present with non-amnestic features. Black patients are half as likely to be diagnosed despite twice as many risk factors. Ethnic disparities in EOAD have not been fully characterized. <h3>Design/Methods:</h3> We retrospectively identified EOAD patients February 2017–February 2022 and collected data on ethnicity, level of education, Montreal Cognitive Assessment (MoCA) scores and clinical presentation. <h3>Results:</h3> Of 88 total patients, 60 (68.8%) identified as Caucasian/White and 28 (31.8%) identified as African American/Black. Age at diagnosis (years) was (57.3 ± 5.24) in Black patients compared to (55.9 ± 5.69) in White patients. Time to diagnosis (years) was on average longer in Black patients (5 ± 9.21) compared with White patients (3.5 ± 6.44) and Black patients were on average more advanced (total MOCA scores) at presentation (12.17 ± 6.91) compared with White patients (15.15 ± 5.92) despite similar education level (in years) among Black patients (14.71 ± 2.30) and White patients (15.21±3.00). An amnestic profile was more common in Black patients (19 or 67.9%) than non-amnestic presentations (9 or 32.1%), although 2 patients (7.14%) presented with visual symptoms suggestive of posterior cortical atrophy (PCA), 5 (17.9%) patients had prominent language symptoms suggestive of logopenic primary progress aphasia (l-PPA) and 1 (3.6%) patient had an executive presentation, suggestive of frontal variant of AD (fAD). Comparatively, non-amnestic presentations were more commonly diagnosed in White patients, with 11 (18.3%) PCA diagnoses, 10 (16.7%) patients with fAD and 8 (13.3%) patients with l-PPA. <h3>Conclusions:</h3> In our cohort, Black patients with EOAD are on average older, more advanced and experience longer delays in diagnosis than their White counterparts. Non-amnestic presentations are more common in White patients. Further work is needed to further characterize the barriers to diagnosis accessibility of care for Black patients with EOAD. <b>Disclosure:</b> Ms. Yang has nothing to disclose. Dr. Yoon has nothing to disclose. Ms. Covaciu has nothing to disclose. The institution of Dr. Seibert has received research support from Retirement Research Foundation. The institution of Dr. Seibert has received research support from Center for Healthcare Delivery Science and Innovation.

Characterizing Early-Onset Alzheimer Disease Using Multiprobe PET/MRI: An AT(N) Framework-Based Study.

Early-onset Alzheimer disease (EOAD) is rare, highly heterogeneous, and associated with poor prognosis. This AT(N) Framework-based study aimed to compare multiprobe PET/MRI findings between EOAD and late-onset Alzheimer disease (LOAD) patients and explore potential imaging biomarkers for characterizing EOAD. Patients with AD who underwent PET/MRI in our PET center were retrospectively reviewed and grouped according to the age at disease onset: EOAD, younger than 60 years; and LOAD, 60 years or older. Clinical characteristics were recorded. All study patients had positive β-amyloid PET imaging; some patients also underwent 18 F-FDG and 18 F-florzolotau PET. Imaging of the EOAD and LOAD groups was compared using region-of-interest and voxel-based analysis. Correlation of onset age and regional SUV ratios were also evaluated. One hundred thirty-three patients were analyzed (75 EOAD and 58 LOAD patients). Sex ( P = 0.515) and education ( P = 0.412) did not significantly differ between groups. Mini-Mental State Examination score was significantly lower in the EOAD group (14.32 ± 6.74 vs 18.67 ± 7.20, P = 0.004). β-Amyloid deposition did not significantly differ between groups. Glucose metabolism in the frontal, parietal, precuneus, temporal, occipital lobe, and supramarginal and angular gyri was significantly lower in the EOAD group (n = 49) than in the LOAD group (n = 44). In voxel-based morphometry analysis, right posterior cingulate/precuneus atrophy was more obvious in the EOAD ( P < 0.001), although no voxel survived family-wise error correction. Tau deposition in the precuneus, parietal lobe, and angular, supramarginal, and right middle frontal gyri was significantly higher in the EOAD group (n = 18) than in the LOAD group (n = 13). Multiprobe PET/MRI showed that tau burden and neuronal damage are more severe in EOAD than in LOAD. Multiprobe PET/MRI may be useful to assess the pathologic characteristics of EOAD.

Regional Comparison of Imaging Biomarkers in the Striatum between Early- and Late-onset Alzheimer's Disease.

Striatal changes in the pathogenesis of Alzheimer's disease (AD) is not fully understood yet. We compared structural and functional image differences in the striatum between patients with early onset AD (EOAD) and late onset AD (LOAD) to investigate whether EOAD harbors autosomal dominant AD like imaging findings. The clinical, neuropsychological and neuroimaging biomarkers of 77 probable AD patients and 107 elderly subjects with normal cognition (NC) from the Alzheimer's Disease Neuroimaging Initiative (ADNI)-2 dataset were analyzed. Enrolled each subject completed a 3-Tesla MRI, baseline 18F-FDG-PET, and baseline 18F-AV-45 (Florbetapir) amyloid PET studies. AD patients were divided into two groups based on the onset age of clinical symptoms (EOAD <65 yrs; LOAD ≥65 yrs). A standardized uptake value ratio of the striatum and subcortical structures was obtained from both amyloid and FDG-PET scans. Structural MR imaging analysis was conducted using a parametric boundary description protocol, SPHARM-PDM. Of the 77 AD patients, 18 were EOAD and 59 were LOAD. Except for age of symptom onset, there were no statistically significant differences between the groups in demographics and detailed neuropsychological test results. 18F-AV-45 amyloid PET showed marked β-amyloid accumulation in the bilateral caudate nucleus and left pallidum in the EOAD group. Intriguingly, the caudate nucleus and putamen showed maintained glucose metabolism in the EOAD group compared to the LOAD group. Our image findings in the striatum of EOAD patients suggest that sporadic EOAD may share some pathophysiological changes noted in autosomal dominant AD.

The role of ethnicity, biological sex, and psychotropic agents in early and late onset Alzheimer's disease.

This study investigates differences in pharmacological and demographic factors among male and female patients with Late-onset Alzheimer's disease (LOAD) and Early-onset Alzheimer's disease (EOAD). Data are from 10,126 AD patients, 9,290 were diagnosed with LOAD, while 836 were diagnosed with EOAD. Data were collected from the Prisma Health Upstate Alzheimer's patients' registry between 2016 and 2021. The logistic regression analysis was used to assess the association between pharmacological and demographic factors in males and females with LOAD and EOAD. In the adjusted analysis for males, patients that were administered memantine [odd ratio (OR) = 1.588, 95% CI, 1.175-2.145, p = 0.003], and buspirone [OR = 1.971, 95% CI, 1.221-3.183, p = 0.006] were more likely to be associated with EOAD, while increasing age [OR = 0.816, 95% CI, 0.799-0.834, p < 0.001] was associated with LOAD. Female patients with a history of alcohol (ETOH) use were more likely to be associated with EOAD while increasing age [OR = 0.845, 95% CI, 0.834-0.857, p < 0.001], treatment with memantine [OR = 0.774, 95% CI, 0.627-0.956, p = 0.017], African Americans [OR = 0.621, 95% CI, 0.462-0.835, p = 0.002] and tobacco use [OR = 0.529, 95% CI, 0.424-0.660, p < 0.001] were associated with LOAD. Our findings identified specific demographic and pharmacological factors associated with males and females with LOAD and EOAD. These findings suggest the need to develop strategies to eliminate disparity in the care of LOAD or EOAD patients.

Age‐at‐Onset and APOE Related Heterogeneity in the Clinical, Plasma Biomarker, and Neuropathologic Presentation of Alzheimer’s Disease (AD)

AbstractBackgroundPatients with sporadic early‐onset AD (EOAD) show less pronounced memory impairment, faster cognitive decline, and greater likelihood of focal cortical syndromes than those with later onset (LOAD), while often lacking the APOE ε4 allele classically associated with younger onset. This heterogeneity could arise from differences in the distribution of AD pathology or presence of concomitant pathologies.MethodWe examined clinical and cognitive heterogeneity in relation to age‐at‐onset, APOE genotype, and concomitant neuropathology (Lewy body, TDP‐43, and vascular) in patients with autopsy‐confirmed severe AD from the National Alzheimer’s Coordinating Center database (N=1750). In patients from the UCSD Alzheimer’s Disease Research Center (N=121) we examined how age‐related heterogeneity relates to differences in distribution of neurofibrillary tangle (NFT) pathology and plasma biomarkers of AD.ResultAge‐at‐onset distribution in APOE ε4‐ patients was bimodal with best separation at age 63. Patients with EOAD (age ≤63) had faster cognitive and functional decline than LOAD regardless of APOE genotype; and were more likely to present with nonmemory cognitive complaints (OR=5.56, 99%CI: 3.32‐9.39), show greater executive dysfunction (β=2.59 SD, 99%CI: 2.10‐3.09), and receive a non‐AD clinical diagnosis (OR=1.54, 99%CI: 1.19‐1.97), particularly for ε4‐ EOAD (p’s&lt;0.01, APOE × age‐at‐onset interactions). Despite this atypicality, groups did not differ in their high rates of AD biomarker positivity, and ε4‐ EOAD patients were most likely to have pure AD without concomitant pathology. TDP‐43 (OR=0.37; 99%CI: 0.18–0.72) and microvascular (OR=0.65; 99%CI: 0.47–0.88) pathology were less common in EOAD, while Lewy pathology was more common in ε4+ (OR=1.48; 99% CI, 1.02–2.17). Midfrontal NFT density was higher in EOAD than LOAD (β= 0.87 SD, 99%CI: 0.44‐1.29). Greater hippocampal NFT density was associated with APOE ε4+ (β=0.49 SD, 99%CI: 0.02‐0.96). Mediation analyses suggest that differences in midfrontal/hippocampal NFT ratio, rather than concomitant neuropathology, mediate the atypical cognitive profiles and decline of EOAD (p&lt;0.01).ConclusionA relatively more neocortical NFT distribution, rather than concomitant non‐AD pathology, accounts for the atypical, non‐memory dominant clinical presentation and rapid progression in EOAD. This suggests that selective cortical vulnerability may explain the earlier‐than‐expected onset and atypical profile in these individuals without the APOE ε4 risk allele.