Browsing by Author "Hall, Kathleen S."

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    Association of Long Runs of Homozygosity With Alzheimer Disease Among African American Individuals
    (American Medical Association, 2015-11) Ghani, Mahdi; Reitz, Christiane; Cheng, Rong; Vardarajan, Badri Narayan; Jun, Gyungah; Sato, Christine; Naj, Adam; Rajbhandary, Ruchita; Wang, Li-San; Valladares, Otto; Lin, Chiao-Feng; Larson, Eric B.; Graff-Radford, Neill R.; Evans, Denis; De Jager, Philip L.; Crane, Paul K.; Buxbaum, Joseph D.; Murrell, Jill R.; Raj, Towfique; Ertekin-Taner, Nilufer; Logue, Mark; Baldwin, Clinton T.; Green, Robert C.; Barnes, Lisa L.; Cantwell, Laura B.; Fallin, M. Daniele; Go, Rodney C. P.; Griffith, Patrick A.; Obisesan, Thomas O.; Manly, Jennifer J.; Lunetta, Kathryn L.; Kamboh, M. Ilyas; Lopez, Oscar L.; Bennett, David A.; Hendrie, Hugh; Hall, Kathleen S.; Goate, Alison M.; Byrd, Goldie S.; Kukull, Walter A.; Foroud, Tatiana M.; Haines, Jonathan L.; Farrer, Lindsay A.; Pericak-Vance, Margaret A.; Lee, Joseph H.; Schellenberg, Gerard D.; St. George-Hyslop, Peter; Mayeux, Richard; Rogaeva, Ekaterina; Department of Psychiatry, IU School of Medicine
    IMPORTANCE: Mutations in known causal Alzheimer disease (AD) genes account for only 1% to 3% of patients and almost all are dominantly inherited. Recessive inheritance of complex phenotypes can be linked to long (>1-megabase [Mb]) runs of homozygosity (ROHs) detectable by single-nucleotide polymorphism (SNP) arrays. OBJECTIVE: To evaluate the association between ROHs and AD in an African American population known to have a risk for AD up to 3 times higher than white individuals. DESIGN, SETTING, AND PARTICIPANTS: Case-control study of a large African American data set previously genotyped on different genome-wide SNP arrays conducted from December 2013 to January 2015. Global and locus-based ROH measurements were analyzed using raw or imputed genotype data. We studied the raw genotypes from 2 case-control subsets grouped based on SNP array: Alzheimer's Disease Genetics Consortium data set (871 cases and 1620 control individuals) and Chicago Health and Aging Project-Indianapolis Ibadan Dementia Study data set (279 cases and 1367 control individuals). We then examined the entire data set using imputed genotypes from 1917 cases and 3858 control individuals. MAIN OUTCOMES AND MEASURES: The ROHs larger than 1 Mb, 2 Mb, or 3 Mb were investigated separately for global burden evaluation, consensus regions, and gene-based analyses. RESULTS: The African American cohort had a low degree of inbreeding (F ~ 0.006). In the Alzheimer's Disease Genetics Consortium data set, we detected a significantly higher proportion of cases with ROHs greater than 2 Mb (P = .004) or greater than 3 Mb (P = .02), as well as a significant 114-kilobase consensus region on chr4q31.3 (empirical P value 2 = .04; ROHs >2 Mb). In the Chicago Health and Aging Project-Indianapolis Ibadan Dementia Study data set, we identified a significant 202-kilobase consensus region on Chr15q24.1 (empirical P value 2 = .02; ROHs >1 Mb) and a cluster of 13 significant genes on Chr3p21.31 (empirical P value 2 = .03; ROHs >3 Mb). A total of 43 of 49 nominally significant genes common for both data sets also mapped to Chr3p21.31. Analyses of imputed SNP data from the entire data set confirmed the association of AD with global ROH measurements (12.38 ROHs >1 Mb in cases vs 12.11 in controls; 2.986 Mb average size of ROHs >2 Mb in cases vs 2.889 Mb in controls; and 22% of cases with ROHs >3 Mb vs 19% of controls) and a gene-cluster on Chr3p21.31 (empirical P value 2 = .006-.04; ROHs >3 Mb). Also, we detected a significant association between AD and CLDN17 (empirical P value 2 = .01; ROHs >1 Mb), encoding a protein from the Claudin family, members of which were previously suggested as AD biomarkers. CONCLUSIONS AND RELEVANCE: To our knowledge, we discovered the first evidence of increased burden of ROHs among patients with AD from an outbred African American population, which could reflect either the cumulative effect of multiple ROHs to AD or the contribution of specific loci harboring recessive mutations and risk haplotypes in a subset of patients. Sequencing is required to uncover AD variants in these individuals.
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    Dementia incidence declined in African-Americans but not in Yoruba
    (Elsevier, 2016-03) Gao, Sujuan; Ogunniyi, Adesola; Hall, Kathleen S.; Baiyewu, Olesegun; Unverzagt, Frederick W.; Lane, Kathleen A.; Murrell, Jill R.; Gureje, Oye; Hendrie, Hugh C.; Department of Biostatistics, Richard M. Fairbanks School of Public Health
    INTRODUCTION: To compare dementia incidence of African-American and Yoruba cohorts aged ≥70 years enrolled in 1992 and 2001. METHODS: African-Americans residing in Indianapolis and Yoruba in Ibadan, Nigeria without dementia were enrolled in 1992 and 2001 and evaluated every 2-3 years until 2009. The cohorts consist of 1440 African-Americans, 1774 Yoruba in 1992 and 1835 African-Americans and 1895 Yoruba in the 2001 cohorts aged ≥70 years. RESULTS: In African-Americans, dementia and Alzheimer's disease (AD) incidence rates were significantly lower in 2001 than 1992 for all age groups except the oldest group. The overall standardized annual dementia incidence rates were 3.6% (95% confidence interval [CI], 3.2%-4.1%) in the 1992 cohort and 1.4% (95% CI, 1.2%-1.7%) in the 2001 cohort. There was no significant difference in dementia or AD incidence between the Yoruba cohorts. DISCUSSION: Future research is needed to explore the reasons for the differential changes in incidence rates in these two populations.
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    Genetic architecture of age-related cognitive decline in African Americans
    (American Academy of Neurology, 2016-12-21) Raj, Towfique; Chibnik, Lori B.; McCabe, Cristin; Wong, Andus; Replogle, Joseph M.; Yu, Lei; Gao, Sujuan; Unverzagt, Frederick W.; Stranger, Barbara; Murrell, Jill; Barnes, Lisa; Hendrie, Hugh C.; Foroud, Tatiana; Krichevsky, Anna; Bennett, David A.; Hall, Kathleen S.; Evans, Denis A.; De Jager, Philip L.; Department of Biostatistics, Richard M. Fairbanks School of Public Health
    OBJECTIVE: To identify genetic risk factors associated with susceptibility to age-related cognitive decline in African Americans (AAs). METHODS: We performed a genome-wide association study (GWAS) and an admixture-mapping scan in 3,964 older AAs from 5 longitudinal cohorts; for each participant, we calculated a slope of an individual's global cognitive change from neuropsychological evaluations. We also performed a pathway-based analysis of the age-related cognitive decline GWAS. RESULTS: We found no evidence to support the existence of a genomic region which has a strongly different contribution to age-related cognitive decline in African and European genomes. Known Alzheimer disease (AD) susceptibility variants in the ABCA7 and MS4A loci do influence this trait in AAs. Of interest, our pathway-based analyses returned statistically significant results highlighting a shared risk from lipid/metabolism and protein tyrosine signaling pathways between cognitive decline and AD, but the role of inflammatory pathways is polarized, being limited to AD susceptibility. CONCLUSIONS: The genetic architecture of aging-related cognitive in AA individuals is largely similar to that of individuals of European descent. In both populations, we note a surprising lack of enrichment for immune pathways in the genetic risk for cognitive decline, despite strong enrichment of these pathways among genetic risk factors for AD.
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    Genetic Influences on Plasma Homocysteine Levels in African Americans and Yoruba Nigerians.
    (IOS Press, 2015) Kim, Sungeun; Nho, Kwangsik; Ramanan, Vijay K.; Lai, Dongbing; Foroud, Tatiana M.; Lane, Katie; Murrell, Jill R.; Gao, Sujuan; Hall, Kathleen S.; Unverzagt, Frederick W.; Baiyewu, Olusegun; Ogunniyi, Adesola; Gureje, Oye; Kling, Mitchel A.; Doraiswamy, P. Murali; Kaddurah-Daouk, Rima; Hendrie, Hugh C.; Saykin, Andrew J.; Department of Radiology and Imaging Sciences, IU School of Medicine
    Plasma homocysteine, a metabolite involved in key cellular methylation processes seems to be implicated in cognitive functions and cardiovascular health with its high levels representing a potential modifiable risk factor for Alzheimer’s disease (AD) and other dementias. A better understanding of the genetic factors regulating homocysteine levels, particularly in non-white populations, may help in risk stratification analyses of existing clinical trials and may point to novel targets for homocysteine-lowering therapy. To identify genetic influences on plasma homocysteine levels in individuals with African ancestry, we performed a targeted gene and pathway-based analysis using a priori biological information and then to identify new association performed a genome-wide association study. All analyses used combined data from the African American and Yoruba cohorts from the Indianapolis-Ibadan Dementia Project. Targeted analyses demonstrated significant associations of homocysteine and variants within the CBS (Cystathionine beta-Synthase) gene. We identified a novel genome-wide significant association of the AD risk gene CD2AP (CD2-associated protein) with plasma homocysteine levels in both cohorts. Minor allele (T) carriers of identified CD2AP variant (rs6940729) exhibited decreased homocysteine level. Pathway enrichment analysis identified several interesting pathways including the GABA receptor activation pathway. This is noteworthy given the known antagonistic effect of homocysteine on GABA receptors. These findings identify several new targets warranting further investigation in relation to the role of homocysteine in neurodegeneration.
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    Mild Cognitive Impairment, Incidence, Progression, and Reversion: Findings from a Community-based Cohort of Elderly African Americans
    (Elsevier, 2014-07) Gao, Sujuan; Unverzagt, Frederick W.; Hall, Kathleen S.; Lane, Kathleen A.; Murrell, Jill R.; Hake, Ann M.; Smith-Gamble, Valerie; Hendrie, Hugh C.; Department of Biostatistics, School of Public Health
    Objective To examine the long-term outcomes of community-based elderly African Americans by following their transitions from normal cognition to mild cognitive impairment (MCI), and to dementia. Methods Participants were from the community-based Indianapolis Dementia Project. A total of 4104 African Americans were enrolled in 1992 or 2001 and followed until 2009 with regularly scheduled evaluation of cognitive assessment. A two-stage sampling was used at each evaluation to select individuals for extensive clinical assessment following the results of stage one cognitive testing. Age and gender specific incidence, progression and reversion rates for MCI were derived using the person-year method in a dynamic cohort and predicted probabilities from weighted multinomial logistic models of transitional probabilities among normal cognition, MCI and dementia. Results Annual overall incidence rate for MCI is 5.6% (95% CI: 4.6–6.6%). Annual progression rate from MCI to dementia is 5.9% (95% CI: 5.3–6.5%) and annual reversion rate from MCI to normal is 18.6% (95% CI: 16.7–20.4%). Both MCI incidence rates and MCI to dementia progression rates increase with age, while reversion rates from MCI to normal decrease with age. Conclusion MCI progression to dementia is much more frequent in the older age groups than in the younger participants where reversion to normal cognition is more common. Future research is needed to determine factors related to the heterogeneous outcomes in MCI individuals.
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    Novel Alzheimer Disease Risk Loci and Pathways in African American Individuals Using the African Genome Resources Panel
    (American Medical Association, 2021-01-01) Kunkle, Brian W.; Schmidt, Michael; Klein, Hans-Ulrich; Naj, Adam C.; Hamilton-Nelson, Kara L.; Larson, Eric B.; Evans, Denis A.; De Jager, Phil L.; Crane, Paul K.; Buxbaum, Joe D.; Ertekin-Taner, Nilufer; Go, Rodney C.P.; Obisesan, Thomas O.; Kamboh, Ilyas; Bennett, David A.; Hall, Kathleen S.; Goate, Alison M.; Foroud, Tatiana M.; Martin, Eden R.; Wang, Li-Sao; Byrd, Goldie S.; Farrer, Lindsay A.; Haines, Jonathan L.; Schellenberg, Gerard D.; Mayeux, Richard; Pericak-Vance, Margaret A.; Reitz, Christiane; Graff-Radford, Neill R.; Martinez, Izri; Ayodele, Temitope; Logue, Mark W.; Cantwell, Laura B.; Jean-Francois, Melissa; Kuzma, Amanda B.; Adams, L.D.; Vance, Jeffery M.; Cuccaro, Michael L.; Chung, Jaeyoon; Mez, Jesse; Lunetta, Kathryn L.; Jun, Gyungah R.; Lopez, Oscar L.; Hendrie, Hugh C.; Reiman, Eric M.; Kowall, Neil W.; Leverenz, James B.; Small, Scott A.; Levey, Allan I.; Golde, Todd E.; Saykin, Andrew J.; Starks, Takiyah D.; Albert, Marilyn S.; Hyman, Bradley T.; Petersen, Ronald C.; Sano, Mary; Wisniewski, Thomas; Vassar, Robert; Kaye, Jeffrey A.; Henderson, Victor W.; DeCarli, Charles; LaFerla, Frank M.; Brewer, James B.; Miller, Bruce L.; Swerdlow, Russell H.; Van Eldik, Linda J.; Paulson, Henry L.; Trojanowski, John Q.; Chui, Helena C.; Rosenberg, Roger N.; Craft, Suzanne; Grabowski, Thomas J.; Asthana, Sanjay; Morris, John C.; Strittmatter, Stephen M.; Kukull, Walter A.; Psychiatry, School of Medicine
    Importance: Compared with non-Hispanic White individuals, African American individuals from the same community are approximately twice as likely to develop Alzheimer disease. Despite this disparity, the largest Alzheimer disease genome-wide association studies to date have been conducted in non-Hispanic White individuals. In the largest association analyses of Alzheimer disease in African American individuals, ABCA7, TREM2, and an intergenic locus at 5q35 were previously implicated. Objective: To identify additional risk loci in African American individuals by increasing the sample size and using the African Genome Resource panel. Design, setting, and participants: This genome-wide association meta-analysis used case-control and family-based data sets from the Alzheimer Disease Genetics Consortium. There were multiple recruitment sites throughout the United States that included individuals with Alzheimer disease and controls of African American ancestry. Analysis began October 2018 and ended September 2019. Main outcomes and measures: Diagnosis of Alzheimer disease. Results: A total of 2784 individuals with Alzheimer disease (1944 female [69.8%]) and 5222 controls (3743 female [71.7%]) were analyzed (mean [SD] age at last evaluation, 74.2 [13.6] years). Associations with 4 novel common loci centered near the intracellular glycoprotein trafficking gene EDEM1 (3p26; P = 8.9 × 10-7), near the immune response gene ALCAM (3q13; P = 9.3 × 10-7), within GPC6 (13q31; P = 4.1 × 10-7), a gene critical for recruitment of glutamatergic receptors to the neuronal membrane, and within VRK3 (19q13.33; P = 3.5 × 10-7), a gene involved in glutamate neurotoxicity, were identified. In addition, several loci associated with rare variants, including a genome-wide significant intergenic locus near IGF1R at 15q26 (P = 1.7 × 10-9) and 6 additional loci with suggestive significance (P ≤ 5 × 10-7) such as API5 at 11p12 (P = 8.8 × 10-8) and RBFOX1 at 16p13 (P = 5.4 × 10-7) were identified. Gene expression data from brain tissue demonstrate association of ALCAM, ARAP1, GPC6, and RBFOX1 with brain β-amyloid load. Of 25 known loci associated with Alzheimer disease in non-Hispanic White individuals, only APOE, ABCA7, TREM2, BIN1, CD2AP, FERMT2, and WWOX were implicated at a nominal significance level or stronger in African American individuals. Pathway analyses strongly support the notion that immunity, lipid processing, and intracellular trafficking pathways underlying Alzheimer disease in African American individuals overlap with those observed in non-Hispanic White individuals. A new pathway emerging from these analyses is the kidney system, suggesting a novel mechanism for Alzheimer disease that needs further exploration. Conclusions and relevance: While the major pathways involved in Alzheimer disease etiology in African American individuals are similar to those in non-Hispanic White individuals, the disease-associated loci within these pathways differ.
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    Two novel loci, COBL and SLC10A2, for Alzheimer's disease in African Americans
    (Elsevier, 2017-02) Mez, Jesse; Chung, Jaeyoon; Jun, Gyungah; Kriegel, Joshua; Bourlas, Alexandra P.; Sherva, Richard; Logue, Mark W.; Barnes, Lisa L.; Bennett, David A.; Buxbaum, Joseph D.; Byrd, Goldie S.; Crane, Paul K.; Ertekin-Taner, Nilüfer; Evans, Denis; Fallin, M. Daniele; Foroud, Tatiana; Goate, Alison; Graff-Radford, Neill R.; Hall, Kathleen S.; Kamboh, M. Ilyas; Kukull, Walter A.; Larson, Eric B.; Manly, Jennifer J.; Haines, Jonathan L.; Mayeux, Richard; Pericak-Vance, Margaret A.; Schellenberg, Gerard D.; Lunetta, Kathryn L.; Farrer, Lindsay A.; Department of Medical & Molecular Genetics, IU School of Medicine
    INTRODUCTION: African Americans' (AAs) late-onset Alzheimer's disease (LOAD) genetic risk profile is incompletely understood. Including clinical covariates in genetic analyses using informed conditioning might improve study power. METHODS: We conducted a genome-wide association study (GWAS) in AAs employing informed conditioning in 1825 LOAD cases and 3784 cognitively normal controls. We derived a posterior liability conditioned on age, sex, diabetes status, current smoking status, educational attainment, and affection status, with parameters informed by external prevalence information. We assessed association between the posterior liability and a genome-wide set of single-nucleotide polymorphisms (SNPs), controlling for APOE and ABCA7, identified previously in a LOAD GWAS of AAs. RESULTS: Two SNPs at novel loci, rs112404845 (P = 3.8 × 10-8), upstream of COBL, and rs16961023 (P = 4.6 × 10-8), downstream of SLC10A2, obtained genome-wide significant evidence of association with the posterior liability. DISCUSSION: An informed conditioning approach can detect LOAD genetic associations in AAs not identified by traditional GWAS.