Browsing by Author "Lantigua, Rafael A."
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Item Beyond GWAS: Investigating Structural Variants and Their Segregation in Familial Alzheimer’s Disease(Wiley, 2025-01-09) Gunasekaran, Tamil Iniyan; Reyes-Dumeyer, Dolly; Corvelo, André; Clarke, Wayne E.; Evani, Uday S.; Byrska-Bishop, Marta S.; Basile, Anna O.; Runnels, Alexi; Musunuri, Rajeeva O.; Narzisi, Giuseppe; Faber, Kelley M.; Goate, Alison M.; Boeve, Brad F.; Cruchaga, Carlos; Pericak-Vance, Margaret A.; Haines, Jonathan L.; Rosenberg, Roger N.; Tsuang, Debby W.; Rivera Mejia, Diones; Medrano, Martin; Lantigua, Rafael A.; Sweet, Robert; Bennett, David A.; Wilson, Robert S.; Foroud, Tatiana M.; Dalgard, Clifton L.; Mayeux, Richard; Zody, Michael; Vardarajan, Badri N.; Medical and Molecular Genetics, School of MedicineBackground: Late‐Onset Alzheimer’s Disease (LOAD) is characterized by genetic heterogeneity and there is no single model explaining the genetic mode of inheritance. To date, more than 70 genetic loci associated with AD have been identified but they explain only a small proportion of AD heritability. Structural variants (SVs) may explain some of the missing AD heritability, and specifically, their segregation in AD families has yet to be investigated. Method: We analyzed WGS data from 197 NHW families (926 subjects, 58.5% affected) and 214 CH families (1,340 subjects, 59.17% affected). Manta, Absinthe, and MELT were used for large insertions/deletions calling from short‐read WGS, combined with Sniffles2 calls from 4 ONT‐sequenced genomes and an external SV call set from HGSVC on 32 PacBio‐sequenced genomes from the 1000 Genomes Project. Genotyping produced a unified project‐level VCF. We identified 45,251 insertions and 76,566 deletions genome‐wide. Variants were tested for segregation and pathogenicity using Annot‐SV, cadd‐SV, and Variant Effect Predictor. Segregation required SV presence in all affected family members and only in unaffected members five years younger than average disease onset. Result: We identified 453 insertions and 598 deletions segregating in 78.68% and 87.31% of NHW families, respectively. In CH families, 432 insertions and 460 deletions were segregating in 75.23% and 72.90% of the families, respectively. Genes overlapping with the SVs exhibited high expression levels in brain tissues. Notably, around 93% of insertions and 76% of deletions segregating in NHW and CH families were less than 1 kilobase pair (1kbp) in length. A total of 79 insertions and 96 deletions were found to be segregating in both NHW and CH families. Interestingly, a segregating insertion was observed in CH families overlapping within the CACNA2D3 gene, which was previously reported in a CH GWAS for clinical AD. A deletion segregating in NHW overlapped with the PSEN1, and another in a CH family overlapped with the PTK2B gene. Conclusion: Our findings suggested that there are several SVs associated with familial AD across CH and NHW families. Prioritizing the SVs based on their effects on gene function and expression will be helpful in understanding their contributions in AD.Item Blood‐Based Biomarkers to Aid in Alzheimer’s Disease Prediction or Diagnosis: Analysis in a Multi‐Ethnic Cohort Study(Wiley, 2025-01-03) Bahl, Aanya; Honig, Lawrence S.; Kang, Min Suk; Sanchez, Danurys; Reyes-Dumeyer, Dolly; Manly, Jennifer J.; Lantigua, Rafael A.; Dage, Jeffrey L.; Brickman, Adam M.; Vardarajan, Badri N.; Mayeux, Richard; Gu, Yian; Neurology, School of MedicineBackground: Blood‐based biomarkers may aid in the diagnosis of Alzheimer’s Disease (AD), but their contribution may be confounded by the presence of multiple chronic conditions and have not been well‐tested in community populations. In the current study, we aimed to determine whether blood‐based biomarkers can aid in refining a multi‐ethnic, urban clinically diagnosed AD community‐based cohort. Method: We included 546 individuals in the Washington Heights, Hamilton Heights, and Inwood Columbia Aging Project (WHICAP) study in this cross‐sectional study. Six biomarkers, including phosphorylated‐tau‐181 (P‐tau181), total (T‐tau), amyloid‐beta 40 and 42 (Aβ40, Aβ42), Glial Fibrillary Acid Protein (GFAP), and Neurofilament Light Chain (NfL) were measured using Quanterix SIMOA HD‐X platforms. The association between the biomarkers and AD or cognitive impairment was tested using logistic regression, adjusted for age, sex, ethnic group, and years of education. Individuals were subsequently characterized as ‘biomarker positive’ or ‘biomarker negative’ based on combined GFAP and P‐tau181/Aβ42 cut scores. Result: The mean age of individuals was 79.3 years (6.56) and 379 (69.4%) were women, 133 (24.48%), were Non‐Hispanic Black, 153 (28.0%) Non‐Hispanic White, and 248 (45.4%) were Hispanic. A clinical diagnosis of AD was made in 129 (25.49%) individuals. Low Aβ42 (OR = 0.18, [95% CI: 0.04 ‐ 0.92]), low Aβ42/Aβ40 (OR = 0.49, [95% CI: 0.228 ‐ 0.872), and high P‐tau181/Ab42 (OR = 5.494, [95% CI: 1.523 – 20.416]) were associated with a clinical diagnosis of AD suggesting a role as predictive biomarkers. However, the best combination, GFAP and P‐tau181/Aβ42 cut scores, yielded a sensitivity of 41% and specificity of 70.5% for clinically diagnosed AD. The concordance was 54.5% and the discordance was present in both directions. Low education, cardiovascular and other comorbidities might contribute to the discrepancy between biomarker positivity and clinical diagnosis. Conclusion: While GFAP and P‐tau181/Aβ42 levels are associated with AD pathology and can aid in the diagnosis of AD, the presence of multiple chronic conditions may lead to either false positives or negatives. Large multi‐ethnic community cohort studies are needed to further examine the utility of these biomarkers in aiding in the clinical diagnosis of AD.Item Correlation of plasma and neuroimaging biomarkers in Alzheimer’s disease(Wiley, 2022) Brickman, Adam M.; Manly, Jennifer J.; Honig, Lawrence S.; Sanchez, Danurys; Reyes-Dumeyer, Dolly; Lantigua, Rafael A.; Vonsattel, Jean Paul; Teich, Andrew F.; Kang, Min Suk; Dage, Jeffrey L.; Mayeux, Richard; Neurology, School of MedicineBlood-based phosphorylated tau (Ptau) 181 and 217 biomarkers are sensitive and specific for Alzheimer's disease. In this racial/ethnically diverse cohort study, participants were classified as biomarker positive (Ptau+) or negative (Ptau-) based on Ptau 181 and 217 concentrations and as cognitively impaired (Sym) or unimpaired (Asym). The four groups, Ptau-/Asym, Ptau+/Asym, Ptau-/Sym, and Ptau+/Sym, differed by age, APOE-4 allele frequency, total tau, neurofilament light chain, and cortical thickness measured by MRI. Our results add to increasing evidence that plasma Ptau 181 and 217 concentrations are valid Alzheimer's disease biomarkers in diverse populations.Item Evaluation of Plasma Biomarkers for A/T/N Classification of Alzheimer Disease Among Adults of Caribbean Hispanic Ethnicity(American Medical Association, 2023-04-03) Honig, Lawrence S.; Kang, Min Suk; Lee, Annie J.; Reyes-Dumeyer, Dolly; Piriz, Angel; Soriano, Belisa; Franco, Yahaira; Dominguez Coronado, Zoraida; Recio, Patricia; Rivera Mejía, Diones; Medrano, Martin; Lantigua, Rafael A.; Teich, Andrew F.; Dage, Jeffrey L.; Mayeux, Richard; Neurology, School of MedicineImportance: Cerebrospinal fluid (CSF) and plasma biomarkers can detect biological evidence of Alzheimer disease (AD), but their use in low-resource environments and among minority ethnic groups is limited. Objective: To assess validated plasma biomarkers for AD among adults of Caribbean Hispanic ethnicity. Design, setting, and participants: In this decision analytical modeling study, adults were recruited between January 1, 2018, and April 30, 2022, and underwent detailed clinical assessments and venipuncture. A subsample of participants also consented to lumbar puncture. Established CSF cut points were used to define AD biomarker-positive status, allowing determination of optimal cut points for plasma biomarkers in the same individuals. The performance of a panel of 6 plasma biomarkers was then assessed with respect to the entire group. Data analysis was performed in January 2023. Main outcomes and measures: Main outcomes were the association of plasma biomarkers amyloid-β 1-42 (Aβ42), amyloid-β 1-40 (Aβ40), total tau (T-tau), phosphorylated tau181 (P-tau181), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) with AD diagnosis. These biomarkers allow assessment of amyloid (A), neurofibrillary degeneration (T), and neurodegeneration (N) aspects of AD. Statistical analyses performed included receiver operating characteristics, Pearson and Spearman correlations, t tests, and Wilcoxon rank-sum, chi-square, and Fisher exact tests. Exposures: Exposures included age, sex, education, country of residence, apolipoprotein-ε4 (APOE-ε4) allele number, serum creatinine, blood urea nitrogen, and body mass index. Results: This study included 746 adults. Participants had a mean (SD) age of 71.0 (7.8) years, 480 (64.3%) were women, and 154 (20.6%) met clinical criteria for AD. Associations were observed between CSF and plasma P-tau181 (r = .47 [95% CI, 0.32-0.60]), NfL (r = 0.57 [95% CI, 0.44-0.68]), and P-tau181/Aβ42 (r = 0.44 [95% CI, 0.29-0.58]). For AD defined by CSF biomarkers, plasma P-tau181 and P-tau181/Aβ42 provided biological evidence of AD. Among individuals judged to be clinically healthy without dementia, biomarker-positive status was determined by plasma P-tau181 for 133 (22.7%) and by plasma P-tau181/Aβ42 for 104 (17.7%). Among individuals with clinically diagnosed AD, 69 (45.4%) had plasma P-tau181 levels and 89 (58.9%) had P-tau181/Aβ42 levels that were inconsistent with AD. Individuals with biomarker-negative clinical AD status tended to have lower levels of education, were less likely to carry APOE-ε4 alleles, and had lower levels of GFAP and NfL than individuals with biomarker-positive clinical AD. Conclusions and relevance: In this cross-sectional study, plasma P-tau181 and P-tau181/Aβ42 measurements correctly classified Caribbean Hispanic individuals with and without AD. However, plasma biomarkers identified individuals without dementia with biological evidence of AD, and a portion of those with dementia whose AD biomarker profile was negative. These results suggest that plasma biomarkers can augment detection of preclinical AD among asymptomatic individuals and improve the specificity of AD diagnosis.Item Missense and loss-of-function variants at GWAS loci in familial Alzheimer's disease(Wiley, 2024) Gunasekaran, Tamil Iniyan; Reyes-Dumeyer, Dolly; Faber, Kelley M.; Goate, Alison; Boeve, Brad; Cruchaga, Carlos; Pericak-Vance, Margaret; Haines, Jonathan L.; Rosenberg, Roger; Tsuang, Debby; Mejia, Diones Rivera; Medrano, Martin; Lantigua, Rafael A.; Sweet, Robert A.; Bennett, David A.; Wilson, Robert S.; Alba, Camille; Dalgard, Clifton; Foroud, Tatiana; Vardarajan, Badri N.; Mayeux, Richard; Medical and Molecular Genetics, School of MedicineBackground: Few rare variants have been identified in genetic loci from genome-wide association studies (GWAS) of Alzheimer's disease (AD), limiting understanding of mechanisms, risk assessment, and genetic counseling. Methods: Using genome sequencing data from 197 families in the National Institute on Aging Alzheimer's Disease Family Based Study and 214 Caribbean Hispanic families, we searched for rare coding variants within known GWAS loci from the largest published study. Results: Eighty-six rare missense or loss-of-function (LoF) variants completely segregated in 17.5% of families, but in 91 (22.1%) families Apolipoprotein E (APOE)-𝜀4 was the only variant segregating. However, in 60.3% of families, APOE 𝜀4, missense, and LoF variants were not found within the GWAS loci. Discussion: Although APOE 𝜀4and several rare variants were found to segregate in both family datasets, many families had no variant accounting for their disease. This suggests that familial AD may be the result of unidentified rare variants. Highlights: Rare coding variants from GWAS loci segregate in familial Alzheimer's disease. Missense or loss of function variants were found segregating in nearly 7% of families. APOE-𝜀4 was the only segregating variant in 29.7% in familial Alzheimer's disease. In Hispanic and non-Hispanic families, different variants were found in segregating genes. No coding variants were found segregating in many Hispanic and non-Hispanic families.Item Plasma p‐tau181, p‐tau217, and other blood‐based Alzheimer's disease biomarkers in a multi‐ethnic, community study(Wiley, 2021) Brickman, Adam M.; Manly, Jennifer J.; Honig, Lawrence S.; Sanchez, Danurys; Reyes-Dumeyer, Dolly; Lantigua, Rafael A.; Lao, Patrick J.; Stern, Yaakov; Vonsattel, Jean Paul; Teich, Andrew F.; Airey, David C.; Proctor, Nicholas Kyle; Dage, Jeffrey L.; Mayeux, Richard; Neurology, School of MedicineIntroduction: Blood-based Alzheimer's disease (AD) biomarkers provide opportunities for community studies and across ethnic groups. We investigated blood biomarker concentrations in the Washington Heights-Inwood Columbia Aging Project (WHICAP), a multi-ethnic community study of aging and dementia. Methods: We measured plasma amyloid beta (Aβ)40, Aβ42, total tau (t-tau), phosphorylated tau (p-tau)181, and p-tau217, and neurofilament light chain (NfL) in 113 autopsied participants (29% with high AD neuropathological changes) and in 300 clinically evaluated individuals (42% with clinical AD). Receiver operating characteristics were used to evaluate each biomarker. We also investigated biomarkers as predictors of incident clinical AD. Results: P-tau181, p-tau217, and NfL concentrations were elevated in pathologically and clinically diagnosed AD. Decreased Aβ42/Aβ40 ratio and increased p-tau217 and p-tau181 were associated with subsequent AD diagnosis. Discussion: Blood-based AD biomarker concentrations are associated with pathological and clinical diagnoses and can predict future development of clinical AD, providing evidence that they can be incorporated into multi-ethnic, community-based studies.Item Risk of Alzheimer's Disease is Associated with Longitudinal Changes in Plasma Biomarkers in the Multiethnic Washington Heights, Inwood Columbia Aging Project Cohort(medRxiv, 2023-08-16) Gu, Yian; Honig, Lawrence S.; Kang, Min Suk; Bahl, Aanya; Sanchez, Danurys; Reyes-Dumeyer, Dolly; Manly, Jennifer J.; Lantigua, Rafael A.; Dage, Jeffrey L.; Brickman, Adam M.; Vardarajan, Badri N.; Mayeux, Richard; Neurology, School of MedicineIntroduction: Alzheimer's disease (AD) biomarkers can help differentiate cognitively unimpaired (CU) individuals from mild cognitive impairment (MCI) and dementia. The role of AD biomarkers in predicting cognitive impairment and AD needs examination. Methods: In 628 CU individuals from a multi-ethnic cohort, Aβ42, Aβ40, phosphorylated tau-181 (P-tau181), glial fibrillary acid protein (GFAP), and neurofilament light chain (NfL) were measured in plasma. Results: Higher baseline levels of P-tau181/Aβ42 ratio were associated with increased risk of incident dementia. A biomarker pattern (with elevated Aβ42/Aβ40 but low P-tau181/Aβ42) was associated with decreased dementia risk. Compared to CU, participants who developed MCI or dementia had a rapid decrease in the biomarker pattern reflecting AD-specific pathological change. Discussion: Elevated levels of AD biomarker P-tau181/Aβ42, by itself or combined with a low Aβ42/Aβ40 level, predicts clinically diagnosed AD. Individuals with a rapid change in these biomarkers may need close monitoring for the potential downward trajectory of cognition.Item Risk of Alzheimer's disease is associated with longitudinal changes in plasma biomarkers in the multi‐ethnic Washington Heights–Hamilton Heights–Inwood Columbia Aging Project (WHICAP) cohort(Wiley, 2024) Gu, Yian; Honig, Lawrence S.; Kang, Min Suk; Bahl, Aanya; Sanchez, Danurys; Reyes-Dumeyer, Dolly; Manly, Jennifer J.; Dage, Jeffrey L.; Lantigua, Rafael A.; Brickman, Adam M.; Vardarajan, Badri N.; Mayeux, Richard; Neurology, School of MedicineBackground: Alzheimer's disease (AD) biomarkers can help differentiate cognitively unimpaired (CU) individuals from mild cognitive impairment (MCI) and dementia. The role of AD biomarkers in predicting cognitive impairment and AD needs examination. Methods: In 628 CU individuals from a multi-ethnic cohort, amyloid beta (Aβ)42, Aβ40, phosphorylated tau-181 (p-tau181), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) were measured in plasma. Results: Higher baseline levels of p-tau181/Aβ42 ratio were associated with an increased risk of incident dementia. A biomarker pattern (with elevated Aβ42/Aβ40 but low p-tau181/Aβ42) was associated with decreased dementia risk. Compared to CU, participants who developed MCI or dementia had a rapid decrease in this protective biomarker pattern reflecting AD-specific pathological change. Discussion: Elevated levels of AD biomarker p-tau181/Aβ42, by itself or combined with a low Aβ42/Aβ40 level, predicts clinically diagnosed AD. Individuals with a rapid change in these biomarkers may need close monitoring for the potential downward trajectory of cognition. Highlights: We discuss a multi-ethnic, urban community study of elderly individuals. The study consisted of a longitudinal assessment over 6 years with repeated clinical assessments. The study used blood-based biomarkers as predictors of mild cognitive impairment and Alzheimer's disease.