Browsing by Author "Kofler, Julia"

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    Adverse Social Exposome by Area Deprivation Index (ADI) and Alzheimer’s Disease and Related Dementias (ADRD) Neuropathology for a National Cohort of Brain Donors within the Neighborhoods Study
    (Wiley, 2025-01-09) Kind, Amy J. H.; Bendlin, Barbara B.; Keller, Sarah A.; Powell, W. Ryan; DeWitt, Amanda; Cheng, Yixuan; Chamberlain, Luke; Lyons Boone, Brittney; Miller, Megan J.; Vik, Stacie M.; Abner, Erin L.; Alosco, Michael L.; Apostolova, Liana G.; Bakulski, Kelly M.; Barnes, Lisa L.; Bateman, James R.; Beach, Thomas G.; Bennett, David A.; Brewer, James B.; Carrion, Carmen; Chodosh, Joshua; Craft, Suzanne; Croff, Raina; Fabio, Anthony; Tomaszewski Farias, Sarah; Goldstein, Felicia; Henderson, Victor W.; Karikari, Thomas; Kofler, Julia; Kucharska-Newton, Anna M.; Lamar, Melissa; Lanata, Serggio; Lepping, Rebecca J.; Lingler, Jennifer H.; Lockhart, Samuel N.; Mahnken, Jonathan D.; Marsh, Karyn; Meyer, Oanh L.; Miller, Bruce L.; Morris, Jill K.; Neugroschl, Judith A.; O'Connor, Maureen K.; Paulson, Henry L.; Perrin, Richard J.; Pierce, Aimee; Raji, Cyrus A.; Reiman, Eric M.; Risacher, Shannon L.; Rissman, Robert A.; Rodriguez Espinoza, Patricia; Sano, Mary; Saykin, Andrew J.; Serrano, Geidy E.; Sultzer, David L.; Whitmer, Rachel A.; Wisniewski, Thomas; Woltjer, Randall; Zhu, Carolyn W.; Neurology, School of Medicine
    Background: Adverse social exposome (indexed by high national Area Deprivation Index [ADI]) is linked to structural inequities and increased risk of clinical dementia diagnosis, yet linkage to ADRD neuropathology remains largely unknown. Early work from single site brain banks suggests a relationship, but assessment in large national cohorts is needed to increase generalizability and depth, particularly for rarer neuropathology findings. Objective: Determine the association between adverse social exposome by ADI and ADRD neuropathology for brain donors from 21 Alzheimer’s Disease Research Center (ADRC) brain banks as part of the on‐going Neighborhoods Study. Methods: All brain donors in participating sites with neuropathology data deposited at the National Alzheimer’s Coordinating Center (NACC) and identifiers for ADI linkage (N = 8,637; Figure 1) were included. Geocoded donor addresses were linked to time‐concordant national ADI percentiles for year of death, categorized into standard groupings of low (ADI 1‐19), medium (20‐49) and high (50‐100) ADI. Neuropathological findings were drawn from NACC and reflected standard assessment practices at time of donation. Logistic regression models, adjusted for sex and age at death, assessed relationships between high ADI and neuropathology findings. Results: Of the N = 8,637 brain donors (Table 1), 2,071 of 2,366 assessed (88%) had AD pathology by NIA‐AA criteria; 4,197 of 6,929 assessed (61%) had cerebral amyloid angiopathy; 2582 of 8092 assessed (32%) had Lewy body pathology; 391 of 2351 assessed (17%) had non‐AD tauopathy; and 586 of 1680 assessed (35%) had TDP‐43 pathology. 2,126(25%) were high ADI; 3,171(37%) medium ADI and 3,340(38%) low ADI with 51% female and average age at death of 81.9 years. As compared to low ADI donors, high ADI brain donors had adjusted odds = 1.35 (95% CI = 0.98‐1.86, p‐value = 0.06) for AD pathology; 1.10 (0.98–1.25, p = 0.11) for cerebral amyloid angiopathy; 1.37 (1.21–1.55, p<0.01) for Lewy body; 1.09 (0.83–1.44, p = 0.53) for non‐AD tauopathy; and 1.40 (1.08‐1.81, p = 0.01) for TDP‐43 pathology (Table 2). Conclusions: This first‐in‐field study provides evidence that the adverse social exposome (high ADI) is strongly associated with an increased risk of Lewy body, an increased risk of TDP‐43, and a trend towards increased AD pathology in a national cohort of brain donors.
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    Aging-related tau astrogliopathy (ARTAG): harmonized evaluation strategy
    (Springer, 2016-01) Kovacs, Gabor G.; Ferrer, Isidro; Alafuzoff, Irina; Attems, Johannes; Budka, Herbert; Cairns, Nigel J.; Crary, John F.; Duyckaerts, Charles; Ghetti, Bernardino; Halliday, Glenda M.; Ironside, James W.; Love, Seth; Mackenzie, Ian R.; Munoz, David G.; Murray, Melissa E.; Nelson, Peter T.; Takahashi, Hitoshi; Trojanowski, John Q.; Ansorge, Olaf; Arzberger, Thomas; Baborie, Atik; Beach, Thomas G.; Bieniek, Kevin F.; Bigio, Eileen H.; Bodi, Istvan; Dugger, Brittany N.; Feany, Mel; Gelpi, Ellen; Gentleman, Stephen M.; Giaccone, Giorgio; Hatanpaa, Kimmo J.; Heale, Richard; Hof, Patrick R.; Hofer, Monika; Hortobágyi, Tibor; Jellinger, Kurt; Jicha, Gregory A.; Ince, Paul; Kofler, Julia; Kövari, Enikö; Kril, Jillian J.; Mann, David M.; Matej, Radoslav; McKee, Ann C.; McLean, Catriona; Milenkovic, Ivan; Montine, Thomas J.; Murayama, Shigeo; Lee, Edward B.; Rahimi, Jasmin; Rodriguez, Roberta D.; Rozemüller, Annemieke; Schneider, Julie A.; Schultz, Christian; Seeley, William; Seilhean, Danielle; Smith, Colin; Tagliavini, Fabrizio; Takao, Masaki; Thal, Dietmar Rudolf; Toledo, Jon B.; Tolnay, Markus; Troncoso, Juan C.; Vinters, Harry V.; Weis, Serge; Wharton, Stephen B.; White III, Charles L.; Wisniewski, Thomas; Woulfe, John M.; Yamada, Masahito; Dicks, Dennis W.; Department of Pathology and Laboratory Medicine, IU School of Medicine
    Pathological accumulation of abnormally phosphorylated tau protein in astrocytes is a frequent, but poorly characterized feature of the aging brain. Its etiology is uncertain, but its presence is sufficiently ubiquitous to merit further characterization and classification, which may stimulate clinicopathological studies and research into its pathobiology. This paper aims to harmonize evaluation and nomenclature of aging-related tau astrogliopathy (ARTAG), a term that refers to a morphological spectrum of astroglial pathology detected by tau immunohistochemistry, especially with phosphorylation-dependent and 4R isoform-specific antibodies. ARTAG occurs mainly, but not exclusively, in individuals over 60 years of age. Tau-immunoreactive astrocytes in ARTAG include thorn-shaped astrocytes at the glia limitans and in white matter, as well as solitary or clustered astrocytes with perinuclear cytoplasmic tau immunoreactivity that extends into the astroglial processes as fine fibrillar or granular immunopositivity, typically in gray matter. Various forms of ARTAG may coexist in the same brain and might reflect different pathogenic processes. Based on morphology and anatomical distribution, ARTAG can be distinguished from primary tauopathies, but may be concurrent with primary tauopathies or other disorders. We recommend four steps for evaluation of ARTAG: (1) identification of five types based on the location of either morphologies of tau astrogliopathy: subpial, subependymal, perivascular, white matter, gray matter; (2) documentation of the regional involvement: medial temporal lobe, lobar (frontal, parietal, occipital, lateral temporal), subcortical, brainstem; (3) documentation of the severity of tau astrogliopathy; and (4) description of subregional involvement. Some types of ARTAG may underlie neurological symptoms; however, the clinical significance of ARTAG is currently uncertain and awaits further studies. The goal of this proposal is to raise awareness of astroglial tau pathology in the aged brain, facilitating communication among neuropathologists and researchers, and informing interpretation of clinical biomarkers and imaging studies that focus on tau-related indicators.
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    Biomarker-Based Approach to α-Synucleinopathies: Lessons from Neuropathology
    (Wiley, 2024) Kovacs, Gabor G.; Grinberg, Lea T.; Halliday, Glenda; Alafuzoff, Irina; Dugger, Brittany N.; Murayama, Shigeo; Forrest, Shelley L.; Martinez-Valbuena, Ivan; Tanaka, Hidetomo; Kon, Tomoya; Yoshida, Koji; Jaunmuktane, Zane; Spina, Salvatore; Nelson, Peter T.; Gentleman, Steve; Alegre-Abarrategui, Javier; Serrano, Geidy E.; Paes, Vitor Ribeiro; Takao, Masaki; Wakabayashi, Koichi; Uchihara, Toshiki; Yoshida, Mari; Saito, Yuko; Kofler, Julia; Diehl Rodriguez, Roberta; Gelpi, Ellen; Attems, Johannes; Crary, John F.; Seeley, William W.; Duda, John E.; Keene, C. Dirk; Woulfe, John; Munoz, David; Smith, Colin; Lee, Edward B.; Neumann, Manuela; White, Charles L., III; McKee, Ann C.; Thal, Dietmar R.; Jellinger, Kurt; Ghetti, Bernardino; Mackenzie, Ian R. A.; Dickson, Dennis W.; Beach, Thomas G.; Pathology and Laboratory Medicine, School of Medicine
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    Genome-wide analyses as part of the international FTLD-TDP whole-genome sequencing consortium reveals novel disease risk factors and increases support for immune dysfunction in FTLD
    (Springer, 2019-02-09) Pottier, Cyril; Ren, Yingxue; Perkerson, Ralph B.; Baker, Matt; Jenkins, Gregory D.; van Blitterswijk, Marka; DeJesus-Hernandez, Mariely; van Rooij, Jeroen G. J.; Murray, Melissa E.; Christopher, Elizabeth; McDonnell, Shannon K.; Fogarty, Zachary; Batzler, Anthony; Tian, Shulan; Vicente, Cristina T.; Matchett, Billie; Karydas, Anna M.; Hsiung, Ging-Yuek Robin; Seelaar, Harro; Mol, Merel O.; Finger, Elizabeth C.; Graff, Caroline; Öijerstedt, Linn; Neumann, Manuela; Heutink, Peter; Synofzik, Matthis; Matthis, Carlo; Prudlo, Johannes; Rizzu, Patrizia; Simon-Sanchez, Javier; Edbauer, Dieter; Roeber, Sigrun; Diehl-Schmid, Janine; Evers, Bret M.; King, Andrew; Mesulam, M. Marsel; Weintraub, Sandra; Geula, Changiz; Bieniek, Kevin F.; Petrucelli, Leonard; Ahern, Geoffrey L.; Reiman, Eric M.; Woodruff, Bryan K.; Caselli, Richard J.; Huey, Edward D.; Farlow, Martin R.; Grafman, Jordan; Mead, Simon; Grinberg, Lea T.; Spina, Salvatore; Grossman, Murray; Irwin, David J.; Lee, Edward B.; Suh, EunRan; Snowden, Julie; Mann, David; Ertekin-Taner, Nilufer; Uitti, Ryan J.; Wszolek, Zbigniew K.; Josephs, Keith A.; Parisi, Joseph E.; Knopman, David S.; Petersen, Ronald C.; Hodges, John R.; Piguet, Olivier; Geier, Ethan G.; Yokoyama, Jennifer S.; Rissman, Robert A.; Rogaeva, Ekaterina; Keith, Julia; Zinman, Lorne; Tartaglia, Maria Carmela; Cairns, Nigel J.; Cruchaga, Carlos; Ghetti, Bernardino; Kofler, Julia; Lopez, Oscar L.; Beach, Thomas G.; Arzberger, Thomas; Herms, Jochen; Honig, Lawrence S.; Vonsattel, Jean Paul; Halliday, Glenda M.; Kwok, John B.; White, Charles L.; Gearing, Marla; Glass, Jonathan; Rollinson, Sara; Pickering-Brown, Stuart; Rohrer, Jonathan D.; Trojanowski, John Q.; Van Deerlin, Vivianna; Bigio, Eileen H.; Troakes, Claire; Al-Sarraj, Safa; Asmann, Yan; Miller, Bruce L.; Graff-Radford, Neill R.; Boeve, Bradley F.; Seeley, William W.; Mackenzie, Ian R. A.; van Swieten, John C.; Dickson, Dennis W.; Biernacka, Joanna M.; Rademakers, Rosa; Neurology, School of Medicine
    Frontotemporal lobar degeneration with neuronal inclusions of the TAR DNA-binding protein 43 (FTLD-TDP) represents the most common pathological subtype of FTLD. We established the international FTLD-TDP whole genome sequencing consortium to thoroughly characterize the known genetic causes of FTLD-TDP and identify novel genetic risk factors. Through the study of 1,131 unrelated Caucasian patients, we estimated that C9orf72 repeat expansions and GRN loss-of-function mutations account for 25.5% and 13.9% of FTLD-TDP patients, respectively. Mutations in TBK1 (1.5%) and other known FTLD genes (1.4%) were rare, and the disease in 57.7% of FTLD-TDP patients was unexplained by the known FTLD genes. To unravel the contribution of common genetic factors to the FTLD-TDP etiology in these patients, we conducted a two-stage association study comprising the analysis of whole-genome sequencing data from 517 FTLD-TDP patients and 838 controls, followed by targeted genotyping of the most associated genomic loci in 119 additional FTLD-TDP patients and 1653 controls. We identified three genome-wide significant FTLD-TDP risk loci: one new locus at chromosome 7q36 within the DPP6 gene led by rs118113626 (pvalue=4.82e-08, OR=2.12), and two known loci: UNC13A, led by rs1297319 (pvalue=1.27e-08, OR=1.50) and HLA-DQA2 led by rs17219281 (pvalue=3.22e-08, OR=1.98). While HLA represents a locus previously implicated in clinical FTLD and related neurodegenerative disorders, the association signal in our study is independent from previously reported associations. Through inspection of our whole genome sequence data for genes with an excess of rare loss-of-function variants in FTLD-TDP patients (n≥3) as compared to controls (n=0), we further discovered a possible role for genes functioning within the TBK1-related immune pathway (e.g. DHX58, TRIM21, IRF7) in the genetic etiology of FTLD-TDP. Together, our study based on the largest cohort of unrelated FTLD-TDP patients assembled to date provides a comprehensive view of the genetic landscape of FTLD-TDP, nominates novel FTLD-TDP risk loci, and strongly implicates the immune pathway in FTLD-TDP pathogenesis.
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    Increased fibrin deposition in the brains of individuals with Down syndrome and Alzheimer’s disease
    (Wiley, 2025-01-03) Du, Annie; Flores-Aguilar, Lisi; Edwards, Natalie C.; Lao, Patrick J.; Ryu, Jae Kyu; Akassoglou, Katerina; Wilcock, Donna M.; Kofler, Julia; Ikonomovic, Milos D.; Lai, Florence; Brickman, Adam M.; Head, Elizabeth; Neurology, School of Medicine
    Background: Individuals with Down syndrome (DS) have an increased genetic risk of developing Alzheimer’s disease (AD), with most adults developing AD neuropathology in their 40s. Despite having a low frequency of systemic vascular risk factors such as hypertension and atherosclerosis, adults with DS display cerebrovascular pathology, including microbleeds, microinfarcts, and cerebral amyloid angiopathy. This suggests that blood‐brain barrier (BBB) integrity may be compromised allowing the extravasation of blood proteins in the brain parenchyma. The blood coagulation factor fibrin promotes immune‐mediated neurodegeneration and is a marker of BBB disruption in a wide range of neurological diseases. This study investigated the severity of fibrin deposition as a measure of BBB integrity in the brains of adults with DS and AD pathology (DSAD). We hypothesized that fibrin deposition is increased in DSAD in comparison to neurotypical controls without DS or AD. Method: Fibrin immunoreactivity was assessed by free‐floating immunohistochemistry in 30µm tissue sections from the occipital cortex from neurotypical controls (n = 12; 41‐65 years old) and DSAD (n = 12; 46‐66 years old). Using whole slide imaging, brain sections were digitized, and the severity of fibrin deposition was scored using Aperio Imagescope. Result: Individuals with DSAD display significantly higher fibrin deposition in the white and grey matter of the occipital cortex in comparison to the age‐matched neurotypical controls (p<0.0001). Conclusion: Neurotypical controls display minimal fibrin deposition in the brain parenchyma and perivascular space. However, compared to neurotypical controls, adults with DS at advanced stages of AD neuropathology display significant fibrin deposition in the occipital cortex, suggesting that the BBB may be compromised in this population.
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    Over‐Representation of Extremely Wealthy Neighborhood Social Exposomes for Brain Donors within Alzheimer’s Disease Research Center Brain Banks assessed by the Neighborhoods Study
    (Wiley, 2025-01-09) Kind, Amy J. H.; Bendlin, Barbara B.; Powell, W. Ryan; DeWitt, Amanda; Cheng, Yixuan; Chamberlain, Luke; Sharrow, Jessica; Lyons Boone, Brittney; Abner, Erin L.; Alosco, Michael L.; Apostolova, Liana G.; Bakulski, Kelly M.; Barnes, Lisa L.; Bateman, James R.; Beach, Thomas G.; Bennett, David A.; Brewer, James B.; Carrion, Carmen; Chodosh, Joshua; Craft, Suzanne; Croff, Raina; Fabio, Anthony; Tomaszewski Farias, Sarah; Goldstein, Felicia; Henderson, Victor W.; Karikari, Thomas K.; Kofler, Julia; Kucharska-Newton, Anna M.; Lamar, Melissa; Lanata, Serggio; Lepping, Rebecca J.; Lingler, Jennifer H.; Lockhart, Samuel N.; Mahnken, Jonathan D.; Marsh, Karyn; Meyer, Oanh L.; Miller, Bruce L.; Morris, Jill K.; Neugroschl, Judith A.; O'Connor, Maureen K.; Paulson, Henry L.; Perrin, Richard J.; Pettigrew, Corinne; Pierce, Aimee; Raji, Cyrus A.; Reiman, Eric M.; Risacher, Shannon L.; Rissman, Robert A.; Rodriguez Espinoza, Patricia; Sano, Mary; Saykin, Andrew J.; Serrano, Geidy E.; Soldan, Anja; Sultzer, David L.; Whitmer, Rachel A.; Wisniewski, Thomas; Woltjer, Randall; Zhu, Carolyn W.; Radiology and Imaging Sciences, School of Medicine
    Background: Adverse social exposome (indexed by national Area Deprivation Index [ADI] 80‐100 or ‘high ADI’) is linked to structural inequities and increased risk of Alzheimer’s disease neuropathology. Twenty percent of the US population resides within high ADI areas, predominantly in inner cities, tribal reservations and rural areas. The percentage of brain donors from high ADI areas within the Alzheimer’s Disease Research Center (ADRC) brain bank system is unknown. Objective: Determine ADI for brain donors from 21 ADRC sites as part of the on‐going Neighborhoods Study. Methods: All brain donors in participating ADRC sites with NACC neuropathology data and personal identifiers for ADI linkage (N = 8,637) were included (Figure 1). Geocoded donor addresses were linked to time‐concordant ADI percentiles for year of death. Results: Overall, only 5.6% of ADRC brain donors (N = 488) resided in a high ADI (disadvantaged) neighborhood at death. The remaining donors resided in more advantaged neighborhoods, with nearly 40% of donors living in the wealthiest quintile of neighborhoods, and over 300 brain donors originating from the wealthiest 1% of US neighborhoods (Figure 2). Donors from high ADI (disadvantaged) neighborhoods identified as 87% White (n = 424), 11% Black (55), 1% Multiracial (6) and <1% other/unknown race (3), with 1% Hispanic (5). None identified as American Indian/Alaska Native or Native Hawaiian/Pacific Islander/Asian. In comparison, donors from low ADI neighborhoods were 94% White (n = 7680), 3% Black (273), 1% Multiracial (75), <1% American Indian/Alaska Native (11), <1% Native Hawaiian/Pacific Islander/Asian (60), and <1% other/unknown race (50), with 3% Hispanic (230). Sex distribution was similar (54%, 51% female, respectively). Inclusion of high ADI donors varied dramatically across the 21 ADRC brain banks from a low of 0.6% to high of 20% of all a site’s donors (Figure 3). Conclusions: ADI was determined for over 8,600 brain donors in the ADRC system, demonstrating a marked over‐representation of donors from very low ADI (extremely wealthy) neighborhoods, in addition to site‐to‐site variability. This is the first time a comprehensive cross‐sectional social exposome assessment of this nature has been performed, opening windows for additional mechanistic study of the social exposome on brain pathology. Life course ADI assessments are on‐going.
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    Potential genetic modifiers of disease risk and age at onset in patients with frontotemporal lobar degeneration and GRN mutations: a genome-wide association study
    (Elsevier, 2018-06) Pottier, Cyril; Zhou, Xiaolai; Perkerson, Ralph B.; Baker, Matt; Jenkins, Gregory D.; Serie, Daniel J.; Ghidoni, Roberta; Benussi, Luisa; Binetti, Giuliano; de Munain, Adolfo López; Zulaica, Miren; Moreno, Fermin; Le Ber, Isabelle; Pasquier, Florence; Hannequin, Didier; Sánchez-Valle, Raquel; Antonell, Anna; Lladó, Albert; Parsons, Tammee M.; Finch, NiCole A.; Finger, Elizabeth C.; Lippa, Carol F.; Huey, Edward D.; Neumann, Manuela; Heutink, Peter; Synofzik, Matthis; Wilke, Carlo; Rissman, Robert A.; Slawek, Jaroslaw; Sitek, Emilia; Johannsen, Peter; Nielsen, Jørgen E.; Ren, Yingxue; van Blitterswijk, Marka; DeJesus-Hernandez, Mariely; Christopher, Elizabeth; Murray, Melissa E.; Bieniek, Kevin F.; Evers, Bret M.; Ferrari, Camilla; Rollinson, Sara; Richardson, Anna; Scarpini, Elio; Fumagalli, Giorgio G.; Padovani, Alessandro; Hardy, John; Momeni, Parastoo; Ferrari, Raffaele; Frangipane, Francesca; Maletta, Raffaele; Anfossi, Maria; Gallo, Maura; Petrucelli, Leonard; Suh, EunRan; Lopez, Oscar L.; Wong, Tsz H.; van Rooij, Jeroen G. J.; Seelaar, Harro; Mead, Simon; Caselli, Richard J.; Reiman, Eric M.; Sabbagh, Marwan Noel; Kjolby, Mads; Nykjaer, Anders; Karydas, Anna M.; Boxer, Adam L.; Grinberg, Lea T.; Grafman, Jordan; Spina, Salvatore; Oblak, Adrian; Mesulam, M-Marsel; Weintraub, Sandra; Geula, Changiz; Hodges, John R.; Piguet, Olivier; Brooks, William S.; Irwin, David J.; Trojanowski, John Q.; Lee, Edward B.; Josephs, Keith A.; Parisi, Joseph E.; Ertekin-Taner, Nilüfer; Knopman, David S.; Nacmias, Benedetta; Piaceri, Irene; Bagnoli, Silvia; Sorbi, Sandro; Gearing, Marla; Glass, Jonathan; Beach, Thomas G.; Black, Sandra E.; Masellis, Mario; Rogaeva, Ekaterina; Vonsattel, Jean-Paul; Honig, Lawrence S.; Kofler, Julia; Bruni, Amalia C.; Snowden, Julie; Mann, David; Pickering-Brown, Stuart; Diehl-Schmid, Janine; Winkelmann, Juliane; Galimberti, Daniela; Graff, Caroline; Öijerstedt, Linn; Troakes, Claire; Al-Sarraj, Safa; Cruchaga, Carlos; Cairns, Nigel J.; Rohrer, Jonathan D.; Halliday, Glenda M.; Kwok, John B.; van Swieten, John C.; White, Charles L.; Ghetti, Bernardino; Murell, Jill R.; Mackenzie, Ian R. A.; Hsiung, Ging-Yuek R.; Borroni, Barbara; Rossi, Giacomina; Tagliavini, Fabrizio; Wszolek, Zbigniew K.; Petersen, Ronald C.; Bigio, Eileen H.; Grossman, Murray; Van Deerlin, Vivianna M.; Seeley, William W.; Miller, Bruce L.; Graff-Radford, Neill R.; Boeve, Bradley F.; Dickson, Dennis W.; Biernacka, Joanna M.; Rademakers, Rosa; Pathology and Laboratory Medicine, School of Medicine
    BACKGROUND: Loss-of-function mutations in GRN cause frontotemporal lobar degeneration (FTLD). Patients with GRN mutations present with a uniform subtype of TAR DNA-binding protein 43 (TDP-43) pathology at autopsy (FTLD-TDP type A); however, age at onset and clinical presentation are variable, even within families. We aimed to identify potential genetic modifiers of disease onset and disease risk in GRN mutation carriers. METHODS: The study was done in three stages: a discovery stage, a replication stage, and a meta-analysis of the discovery and replication data. In the discovery stage, genome-wide logistic and linear regression analyses were done to test the association of genetic variants with disease risk (case or control status) and age at onset in patients with a GRN mutation and controls free of neurodegenerative disorders. Suggestive loci (p<1 × 10-5) were genotyped in a replication cohort of patients and controls, followed by a meta-analysis. The effect of genome-wide significant variants at the GFRA2 locus on expression of GFRA2 was assessed using mRNA expression studies in cerebellar tissue samples from the Mayo Clinic brain bank. The effect of the GFRA2 locus on progranulin concentrations was studied using previously generated ELISA-based expression data. Co-immunoprecipitation experiments in HEK293T cells were done to test for a direct interaction between GFRA2 and progranulin. FINDINGS: Individuals were enrolled in the current study between Sept 16, 2014, and Oct 5, 2017. After quality control measures, statistical analyses in the discovery stage included 382 unrelated symptomatic GRN mutation carriers and 1146 controls free of neurodegenerative disorders collected from 34 research centres located in the USA, Canada, Australia, and Europe. In the replication stage, 210 patients (67 symptomatic GRN mutation carriers and 143 patients with FTLD without GRN mutations pathologically confirmed as FTLD-TDP type A) and 1798 controls free of neurodegenerative diseases were recruited from 26 sites, 20 of which overlapped with the discovery stage. No genome-wide significant association with age at onset was identified in the discovery or replication stages, or in the meta-analysis. However, in the case-control analysis, we replicated the previously reported TMEM106B association (rs1990622 meta-analysis odds ratio [OR] 0·54, 95% CI 0·46-0·63; p=3·54 × 10-16), and identified a novel genome-wide significant locus at GFRA2 on chromosome 8p21.3 associated with disease risk (rs36196656 meta-analysis OR 1·49, 95% CI 1·30-1·71; p=1·58 × 10-8). Expression analyses showed that the risk-associated allele at rs36196656 decreased GFRA2 mRNA concentrations in cerebellar tissue (p=0·04). No effect of rs36196656 on plasma and CSF progranulin concentrations was detected by ELISA; however, co-immunoprecipitation experiments in HEK293T cells did suggest a direct binding of progranulin and GFRA2. INTERPRETATION: TMEM106B-related and GFRA2-related pathways might be future targets for treatments for FTLD, but the biological interaction between progranulin and these potential disease modifiers requires further study. TMEM106B and GFRA2 might also provide opportunities to select and stratify patients for future clinical trials and, when more is known about their potential effects, to inform genetic counselling, especially for asymptomatic individuals. FUNDING: National Institute on Aging, National Institute of Neurological Disorders and Stroke, Canadian Institutes of Health Research, Italian Ministry of Health, UK National Institute for Health Research, National Health and Medical Research Council of Australia, and the French National Research Agency.