α-synuclein interacts with PrPC to induce cognitive impairment through mGluR5 and NMDAR2B

© 2017 Nature America, Inc., part of Springer Nature. All rights reserved.Synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies, are neurodegenerative disorders that are characterized by the accumulation of α-synuclein (aSyn) in intracellular inclusions known as Lewy bodies. Prefibrillar soluble aSyn oligomers, rather than larger inclusions, are currently considered to be crucial species underlying synaptic dysfunction. We identified the cellular prion protein (PrPC) as a key mediator in aSyn-induced synaptic impairment. The aSyn-associated impairment of long-term potentiation was blocked in Prnp null mice and rescued following PrPC blockade. We found that extracellular aSyn oligomers formed a complex with PrPC that induced the phosphorylation of Fyn kinase via metabotropic glutamate receptors 5 (mGluR5). aSyn engagement of PrPC and Fyn activated NMDA receptor (NMDAR) and altered calcium homeostasis. Blockade of mGluR5-evoked phosphorylation of NMDAR in aSyn transgenic mice rescued synaptic and cognitive deficits, supporting the hypothesis that a receptor-mediated mechanism, independent of pore formation and membrane leakage, is sufficient to trigger early synaptic damage induced by extracellular aSyn.M.T.F., H.V.M. and J.E.C. were supported by individual grants from Fundação para a Ciência e Tecnologia (FCT) (SFRH/BD/52228/2013; SFRH/BPD/109347/2015; SFRH/BPD/87647/2012); L.V.L. and T.F.O. were supported by a grant from the Fritz Thyssen Stiftung (Az. 10.12.2.165), Germany. L.V.L. received an iMM Lisboa internal fund (BIG – Breakthrough Idea Grant) for part of the project. L.V.L. is an Investigator FCT, Portugal. T.F.O. is supported by the DFG Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Germany. LISBOA-01-0145-FEDER-007391, project co-financed by FEDER, POR Lisboa 2020 - Programa Operacional Regional de Lisboa, from PORTUGAL 2020 and by Fundação para a Ciência e a Tecnologia.info:eu-repo/semantics/publishedVersio

How satisfied are cervical dystonia patients after 3 years of botulinum toxin type A treatment? Results from a prospective, long-term observational study

Background Patients with cervical dystonia (CD) typically require regular injections of botulinum toxin to maintain symptomatic control. We aimed to document long-term patient satisfaction with CD symptom control in a large cohort of patients treated in routine practice. Methods This was a prospective, international, observational study (NCT01753349) following the course of adult CD treated with botulinum neurotoxin type A (BoNT-A) over 3 years. A comprehensive clinical assessment status was performed at each injection visit and subjects reported satisfaction in two ways: satisfaction with symptom control at peak effect and at the end of treatment cycle. Results Subject satisfaction remained relatively stable from the first to the last injection visit. At 3 years, 89.9% of subjects reported satisfaction with symptom control at peak effect and 55.6% reported satisfaction with symptom control at end of treatment cycle. By contrast, objective ratings of CD severity showed an overall reduction over 3 years. Mean ± SD Toronto Western Spasmodic Rating Scale (TWSTRS) Total scores (clinician assessed at end of treatment cycle) decreased from 31.59 ± 13.04 at baseline to 24.49 ± 12.43 at 3 years (mean ± SD reduction from baseline of − 6.97 ± 11.56 points). Tsui scale scores also showed gradual improvement; the percent of subjects with a tremor component score of 4 reduced from 12.4% at baseline to 8.1% at 3 years. Conclusions Despite objective clinical improvements over 3 years, subject satisfaction with symptom control remained relatively constant, indicating that factors other than symptom control also play a role in patient satisfaction

β-Defensin genomic copy number does not influence the age of onset in Huntington's Disease

none498siHuntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by the abnormal expansion of a CAG triplet repeat tract in the huntingtin gene. While the length of this CAG expansion is the major determinant of the age of onset (AO), other genetic factors have also been shown to play a modulatory role. Recent evidence suggests that neuroinflammations is a pivotal factor in the pathogenesis of HD, and that targeting this process may have important therapeutic ramifications. The human β-defensin 2 (hBD2)- encoded by DEFB4- is an antimicrobial peptide that exhibits inducible expression in astrocytes during inflammation and is an important regulator of innate and adaptive immune response. Therefore, DEFB4 may contribute to the neuroinflammatory processes observed in HD.openVittori A, Orth M, Roos RA, Outeiro TF, Giorgini F, Hollox EJ, Bachoud-Levi AC, Bentivoglio AR, Biunno I, Bonelli RM, Burgunder JM, Dunnett SB, Ferreira JJ, Handley OJ, Heiberg A, Illmann T, Landwehrmeyer GB, Levey J, Martinez-Jaurrieta MD, Nielsen JE, Pro Koivisto S, Piiiviirinta M, Roos RA, Sebastian AR, Tabrizi SJ, Vandenberghe W, Verellen-Dumoulin C, Zaremba J, Uhrova T, Wahlstrom J, Barth K, Correia-Guedes L, Finisterra AM, Bascuiiana Garde M, Betz S, Bos R, Ecker D, Handley OJ, Held C, Koppers K, Laura M, Descals AM, Mestre T, Monza D, Townhill J, Padieu H, Paterski L, Peppa N, Rialland A, Røren N, Sasinkova P, Trigo Cubillo P, van Walsem M, Witjes-Ane MN, Yudina E, Zielonka D, Zielonka E, Zinzi P, Bonelli RM, Herranhof B, HOd A, Kapfhammer HP, Koppitz M, Magnet M, Otti D, Painold A, Reisinge K, Scheib M, Hecht K, Lilek S, Muller N, Schoggl H, Ullah J, Ribal P, Verellen-Dumoulin C, Klempff J, Majerova V, Roth J, Hjermind LE, Jakobsen O, Vinthev-Jensen T, Larsen IU, Nielsen JE, Stokholm J, Hiivola H, Martikainen K, Tuuha K, Santala M, Milkereit E, Kosinski CM, Probst D, Reetz K, Sass C, Schiefer J, Schlangen C, Werner CJ, Andrich J, Ellrichmann G, Hoffmann R, Kaminski B, Saft C, Stamm C, Lange H, Lohle M, Schmidt S, Storch A, Wolz A, Wolz M, Capetian P, Lambeck J, Zucker B, Boelmans K, Ganos C, Hidding U, Lewerenz J, Miinchau A, Orth M, Schmalfeld J, Stubbe L, Zittel S, Heinicke W, Ribbat M, Longinus B, Miihlau M, Peinemann A, Stiidtler M, Weindl A, Winkelmann J, Ziegler C, Bechtel N, Beckmann H, Bohlen S, Holzner E, Lange H, Reilmann R, Rohm S, Rumpf S, Schepers S, Dose M, Leythaeuser G, Marquard R, Raab T, Schrenk C, Schuierer M, Barth K, Buck A, Ecker D, Eschenbach C, Held C, Landwehrmeyer B, Lezius F, Nepper S, Niess A, Orth M, Schwenk D, Siissmuth S, Trautmann S, Weydt P, Cormio C, de Tommaso M, Sciruicchio V, Serpino C, Ghelli E, Ginestroni A, Bertini E, Massaro F, Mechi C, Paganini M, Piacentini S, Pradella S, Romoli AM, Sorbi S, Abbruzzese G, Ferrandes MB, Di Maria E, Ferrandes G, Mandich P, Marchese R, Di Donato S, Gellera C, Genitrini S, Mariotti C, Nanetti L, Monza D, Soliveri P, Tomasello C, De Michele G, DiMaio L, Massarelli M, Rinaldi C, Roca A, Rossi F, Russo CV, Salvatore E, Sorrentino P, Tucci T, De Nicola A, Elifani F, Petrollini M, Martino T, Lovo F, Squitieri F, Bentivoglio AR, Catalli C, Di Giacopo R, Fasano A, Frontali M, Guidubaldi A, Ialongo T, Jacopini G, Loria G, Piano C, Piccininni C, Quaranta D, Romano S, Soleti F, Spadaro M, Zinzi P, van Hout MS, van Vugt JP, de Weert A, Bolwijn JJ, Neurologie P, Dekker M, Neurologie P, Leenders KL, van Oostrom JC, Bos R, Dumas EM, Jurgens CK, van den Bogaard SJ, Roos RA, 't Hart EP, Kremer B, Verstappen CC, Heiberg A, van Walsem MR, Frich J, Aaserud O, Wehus R, Bjørgo K, Fannemel M, Gørvell P, Lorentzen E, Koivisto SP, Retterstøl L, Stokke B, Bjørnevoll I, Sando SB, Dziadkiewicz A, Nowak M, Robowski P, Sitek E, Slawek J, Soltan W, Szinwelski M, Blaszczyk M, Boczarska-Jedynak M, Ciach-Wysocka E, Gorzkowska A, Jasinska-Myga B, Opala G, Klodowska G, Stompel D, Ciach-Wysocka E, Banaszkiewicz K, Boewiriska D, Bojakowska-Jaremek K, Neurologii A, Dec M, Krawczyk M, Rudziriska M, Szczudlik A, Szczygiel E, Wasielewska A, Wojcik M, Wojcik M, Bryl A, Ciesielska A, Klimberg A, Marcinkowski J, Samara H, Sempolowicz J, Zielonka D, Janik P, Kalbarczyk A, Kwiecinski H, Jamrozik Z, Antczak J, Jachinska K, Krysa W, Rakowicz M, Richter P, Rola R, Ryglewicz D, Sienkiewicz-Jarosz H, Sulek A, Witkowski G, Zdzienicka E, Zaremba J, Zieora-Jakutowicz K, Coelho M, Correia-Guedes L, Ferreira JJ, Mestre T, Mendes T, Valadas A, Andrade C, Joao PS, Gago M, Garrett C, Joao PS, Guerra MR, Joao PS, Solis P, Herrera CD, Garcia PM, Cubo E, Mariscal N, Sanchez J, Barrero FJ, Alonso-Frech F, Perez MR, Fenollar M, Garda R, Rivera SV, Villanueva C, Alegre J, Bascuiiana M, Ventura MF, Ribas GG, Moreno JL, Cubillo PT, Rufz PJ, Frech FA, Dfaz J, Guerrero R, Dfaz J, Artiga MJ, Dfaz J, Sanchez V, Alcaraz LF, de Ia Arrixaca V, Manzanares S, de Ia Arrixaca V, Perea MF, Reinante G, Arrixaca Ia, Torres MM, Moreau LV, de Ia Arrixaca V, Barbera MA, Guia DB, Hernanz LC, Catena JL, Sebastian R, Ferrer PQ, Carruesco GT, Bas J, Busquets N, Calopa M, Buongiorno MT, Munoz E, Elorza MD, Lopez CD, Terol DS, Robert MF, Rufz BG, Casado AG, Martinez IH, Viladrich CM, Pons R, Roca E, Llesoy JR, Idiago JM, Vergara MR, Garcia SS, Riballo AV, Hoglund A, Palhagen SE, Paucar M, Sandstrom B, Svenningsson P, Reza-Soltani TW, Burgunder JM, Kaelin A, Romero I, Schupbach M, Stebler Y, Zaugg SW, Akhtar S, Crooks J, Curtis A, de Souza J, Rickards H, Wright J, Barker RA, Di Pietro A, Fisher K, Goodman AO, Hill S, Kershaw A, Mason S, O'Keefe D, Swain R, Guzman NV, Busse M, Butcher C, Clenaghan C, Dunnett S, Fullam R, Jones L, Jones U, Khalil H, Minster S, Owen M, Hunt S, Price K, Rosser A, Townhill J, Edwards M, Ho C, McGill M, Pearson P, Porteous M, Brockie P, Foster J, Johns N, McKenzie S, Rothery J, Thomas G, Yates S, Burrows L, Chu C, Fletcher A, Gallantrae D, Harding A, Hamer S, Kraus A, Laver F, Longthorpe M, Markova I, Raman A, Silva M, Thomson A, Wild S, Yardumian P, Hobson E, Jamieson S, Musgrave H, Rowett L, Toscano J, Wild S, Yardumian P, Clayton C, Dipple H, Middleton J, Patino D, Andrews T, Dougherty A, Kavalier F, Golding C, Laing H, Lashwood A, Robertson D, Ruddy D, Whaite A, Santhouse A, Andrews T, Bruno S, Doherty K, Lahiri N, Novak M, Patel A, Rosser E, Tabrizi S, Taylor R, Warner T, Wild E, Arran N, Bek J, Callaghan J, Craufurd D, Fullam R, Howard L, Hare M, Huson S, Johnson L, Jones M, Murphy H, Oughton E, Partington-Janes L, Rogers D, Snowden J, Sollom A, Stopford C, Thompson J, Trender-Gerhard I.Vittori, A; Orth, M; Roos, Ra; Outeiro, Tf; Giorgini, F; Hollox, Ej; Bachoud-Levi, Ac; Bentivoglio, Ar; Biunno, I; Bonelli, Rm; Burgunder, Jm; Dunnett, Sb; Ferreira, Jj; Handley, Oj; Heiberg, A; Illmann, T; Landwehrmeyer, Gb; Levey, J; Martinez-Jaurrieta, Md; Nielsen, Je; Pro Koivisto, S; Piiiviirinta, M; Roos, Ra; Sebastian, Ar; Tabrizi, Sj; Vandenberghe, W; Verellen-Dumoulin, C; Zaremba, J; Uhrova, T; Wahlstrom, J; Barth, K; Correia-Guedes, L; Finisterra, Am; Bascuiiana Garde, M; Betz, S; Bos, R; Ecker, D; Handley, Oj; Held, C; Koppers, K; Laura, M; Descals, Am; Mestre, T; Monza, D; Townhill, J; Padieu, H; Paterski, L; Peppa, N; Rialland, A; Røren, N; Sasinkova, P; Trigo Cubillo, P; van Walsem, M; Witjes-Ane, Mn; Yudina, E; Zielonka, D; Zielonka, E; Zinzi, P; Bonelli, Rm; Herranhof, B; Hod, A; Kapfhammer, Hp; Koppitz, M; Magnet, M; Otti, D; Painold, A; Reisinge, K; Scheib, M; Hecht, K; Lilek, S; Muller, N; Schoggl, H; Ullah, J; Ribal, P; Verellen-Dumoulin, C; Klempff, J; Majerova, V; Roth, J; Hjermind, Le; Jakobsen, O; Vinthev-Jensen, T; Larsen, Iu; Nielsen, Je; Stokholm, J; Hiivola, H; Martikainen, K; Tuuha, K; Santala, M; Milkereit, E; Kosinski, Cm; Probst, D; Reetz, K; Sass, C; Schiefer, J; Schlangen, C; Werner, Cj; Andrich, J; Ellrichmann, G; Hoffmann, R; Kaminski, B; Saft, C; Stamm, C; Lange, H; Lohle, M; Schmidt, S; Storch, A; Wolz, A; Wolz, M; Capetian, P; Lambeck, J; Zucker, B; Boelmans, K; Ganos, C; Hidding, U; Lewerenz, J; Miinchau, A; Orth, M; Schmalfeld, J; Stubbe, L; Zittel, S; Heinicke, W; Ribbat, M; Longinus, B; Miihlau, M; Peinemann, A; Stiidtler, M; Weindl, A; Winkelmann, J; Ziegler, C; Bechtel, N; Beckmann, H; Bohlen, S; Holzner, E; Lange, H; Reilmann, R; Rohm, S; Rumpf, S; Schepers, S; Dose, M; Leythaeuser, G; Marquard, R; Raab, T; Schrenk, C; Schuierer, M; Barth, K; Buck, A; Ecker, D; Eschenbach, C; Held, C; Landwehrmeyer, B; Lezius, F; Nepper, S; Niess, A; Orth, M; Schwenk, D; Siissmuth, S; Trautmann, S; Weydt, P; Cormio, C; de Tommaso, M; Sciruicchio, V; Serpino, C; Ghelli, E; Ginestroni, A; Bertini, E; Massaro, F; Mechi, C; Paganini, M; Piacentini, S; Pradella, S; Romoli, Am; Sorbi, S; Abbruzzese, G; Ferrandes, Mb; Di Maria, E; Ferrandes, G; Mandich, P; Marchese, R; Di Donato, S; Gellera, C; Genitrini, S; Mariotti, C; Nanetti, L; Monza, D; Soliveri, P; Tomasello, C; De Michele, G; Dimaio, L; Massarelli, M; Rinaldi, C; Roca, A; Rossi, F; Russo, Cv; Salvatore, E; Sorrentino, P; Tucci, T; De Nicola, A; Elifani, F; Petrollini, M; Martino, T; Lovo, F; Squitieri, F; Bentivoglio, Ar; Catalli, C; Di Giacopo, R; Fasano, A; Frontali, M; Guidubaldi, A; Ialongo, T; Jacopini, G; Loria, G; Piano, C; Piccininni, C; Quaranta, D; Romano, S; Soleti, F; Spadaro, M; Zinzi, P; van Hout, Ms; van Vugt, Jp; de Weert, A; Bolwijn, Jj; Neurologie, P; Dekker, M; Neurologie, P; Leenders, Kl; van Oostrom, Jc; Bos, R; Dumas, Em; Jurgens, Ck; van den Bogaard, Sj; Roos, Ra; 't Hart, Ep; Kremer, B; Verstappen, Cc; Heiberg, A; van Walsem, Mr; Frich, J; Aaserud, O; Wehus, R; Bjørgo, K; Fannemel, M; Gørvell, P; Lorentzen, E; Koivisto, Sp; Retterstøl, L; Stokke, B; Bjørnevoll, I; Sando, Sb; Dziadkiewicz, A; Nowak, M; Robowski, P; Sitek, E; Slawek, J; Soltan, W; Szinwelski, M; Blaszczyk, M; Boczarska-Jedynak, M; Ciach-Wysocka, E; Gorzkowska, A; Jasinska-Myga, B; Opala, G; Klodowska, G; Stompel, D; Ciach-Wysocka, E; Banaszkiewicz, K; Boewiriska, D; Bojakowska-Jaremek, K; Neurologii, A; Dec, M; Krawczyk, M; Rudziriska, M; Szczudlik, A; Szczygiel, E; Wasielewska, A; Wojcik, M; Wojcik, M; Bryl, A; Ciesielska, A; Klimberg, A; Marcinkowski, J; Samara, H; Sempolowicz, J; Zielonka, D; Janik, P; Kalbarczyk, A; Kwiecinski, H; Jamrozik, Z; Antczak, J; Jachinska, K; Krysa, W; Rakowicz, M; Richter, P; Rola, R; Ryglewicz, D; Sienkiewicz-Jarosz, H; Sulek, A; Witkowski, G; Zdzienicka, E; Zaremba, J; Zieora-Jakutowicz, K; Coelho, M; Correia-Guedes, L; Ferreira, Jj; Mestre, T; Mendes, T; Valadas, A; Andrade, C; Joao, Ps; Gago, M; Garrett, C; Joao, Ps; Guerra, Mr; Joao, Ps; Solis, P; Herrera, Cd; Garcia, Pm; Cubo, E; Mariscal, N; Sanchez, J; Barrero, Fj; Alonso-Frech, F; Perez, Mr; Fenollar, M; Garda, R; Rivera, Sv; Villanueva, C; Alegre, J; Bascuiiana, M; Ventura, Mf; Ribas, Gg; Moreno, Jl; Cubillo, Pt; Rufz, Pj; Frech, Fa; Dfaz, J; Guerrero, R; Dfaz, J; Artiga, Mj; Dfaz, J; Sanchez, V; Alcaraz, Lf; de Ia Arrixaca, V; Manzanares, S; de Ia Arrixaca, V; Perea, Mf; Reinante, G; Arrixaca, Ia; Torres, Mm; Moreau, Lv; de Ia Arrixaca, V; Barbera, Ma; Guia, Db; Hernanz, Lc; Catena, Jl; Sebastian, R; Ferrer, Pq; Carruesco, Gt; Bas, J; Busquets, N; Calopa, M; Buongiorno, Mt; Munoz, E; Elorza, Md; Lopez, Cd; Terol, Ds; Robert, Mf; Rufz, Bg; Casado, Ag; Martinez, Ih; Viladrich, Cm; Pons, R; Roca, E; Llesoy, Jr; Idiago, Jm; Vergara, Mr; Garcia, Ss; Riballo, Av; Hoglund, A; Palhagen, Se; Paucar, M; Sandstrom, B; Svenningsson, P; Reza-Soltani, Tw; Burgunder, Jm; Kaelin, A; Romero, I; Schupbach, M; Stebler, Y; Zaugg, Sw; Akhtar, S; Crooks, J; Curtis, A; de Souza, J; Rickards, H; Wright, J; Barker, Ra; Di Pietro, A; Fisher, K; Goodman, Ao; Hill, S; Kershaw, A; Mason, S; O'Keefe, D; Swain, R; Guzman, Nv; Busse, M; Butcher, C; Clenaghan, C; Dunnett, S; Fullam, R; Jones, L; Jones, U; Khalil, H; Minster, S; Owen, M; Hunt, S; Price, K; Rosser, A; Townhill, J; Edwards, M; Ho, C; Mcgill, M; Pearson, P; Porteous, M; Brockie, P; Foster, J; Johns, N; Mckenzie, S; Rothery, J; Thomas, G; Yates, S; Burrows, L; Chu, C; Fletcher, A; Gallantrae, D; Harding, A; Hamer, S; Kraus, A; Laver, F; Longthorpe, M; Markova, I; Raman, A; Silva, M; Thomson, A; Wild, S; Yardumian, P; Hobson, E; Jamieson, S; Musgrave, H; Rowett, L; Toscano, J; Wild, S; Yardumian, P; Clayton, C; Dipple, H; Middleton, J; Patino, D; Andrews, T; Dougherty, A; Kavalier, F; Golding, C; Laing, H; Lashwood, A; Robertson, D; Ruddy, D; Whaite, A; Santhouse, A; Andrews, T; Bruno, S; Doherty, K; Lahiri, N; Novak, M; Patel, A; Rosser, E; Tabrizi, S; Taylor, R; Warner, T; Wild, E; Arran, N; Bek, J; Callaghan, J; Craufurd, D; Fullam, R; Howard, L; Hare, M; Huson, S; Johnson, L; Jones, M; Murphy, H; Oughton, E; Partington-Janes, L; Rogers, D; Snowden, J; Sollom, A; Stopford, C; Thompson, J; Trender-Gerhard, I

Clinical manifestations of intermediate allele carriers in Huntington disease

Objective: There is controversy about the clinical consequences of intermediate alleles (IAs) in Huntington disease (HD). The main objective of this study was to establish the clinical manifestations of IA carriers for a prospective, international, European HD registry. Methods: We assessed a cohort of participants at risk with <36 CAG repeats of the huntingtin (HTT) gene. Outcome measures were the Unified Huntington's Disease Rating Scale (UHDRS) motor, cognitive, and behavior domains, Total Functional Capacity (TFC), and quality of life (Short Form-36 [SF-36]). This cohort was subdivided into IA carriers (27-35 CAG) and controls (<27 CAG) and younger vs older participants. IA carriers and controls were compared for sociodemographic, environmental, and outcome measures. We used regression analysis to estimate the association of age and CAG repeats on the UHDRS scores. Results: Of 12,190 participants, 657 (5.38%) with <36 CAG repeats were identified: 76 IA carriers (11.56%) and 581 controls (88.44%). After correcting for multiple comparisons, at baseline, we found no significant differences between IA carriers and controls for total UHDRS motor, SF-36, behavioral, cognitive, or TFC scores. However, older participants with IAs had higher chorea scores compared to controls (p 0.001). Linear regression analysis showed that aging was the most contributing factor to increased UHDRS motor scores (p 0.002). On the other hand, 1-year follow-up data analysis showed IA carriers had greater cognitive decline compared to controls (p 0.002). Conclusions: Although aging worsened the UHDRS scores independently of the genetic status, IAs might confer a late-onset abnormal motor and cognitive phenotype. These results might have important implications for genetic counseling. ClinicalTrials.gov identifier: NCT01590589

CAG repeat expansion in Huntington disease determines age at onset in a fully dominant fashion

Objective: Age at onset of diagnostic motor manifestations in Huntington disease (HD) is strongly correlated with an expanded CAG trinucleotide repeat. The length of the normal CAG repeat allele has been reported also to influence age at onset, in interaction with the expanded allele. Due to profound implications for disease mechanism and modification, we tested whether the normal allele, interaction between the expanded and normal alleles, or presence of a second expanded allele affects age at onset of HD motor signs. Methods: We modeled natural log-transformed age at onset as a function of CAG repeat lengths of expanded and normal alleles and their interaction by linear regression. Results: An apparently significant effect of interaction on age at motor onset among 4,068 subjects was dependent on a single outlier data point. A rigorous statistical analysis with a wellbehaved dataset that conformed to the fundamental assumptions of linear regression (e.g., constant variance and normally distributed error) revealed significance only for the expanded CAG repeat, with no effect of the normal CAG repeat. Ten subjects with 2 expanded alleles showed an age at motor onset consistent with the length of the larger expanded allele. Conclusions: Normal allele CAG length, interaction between expanded and normal alleles, and presence of a second expanded allele do not influence age at onset of motor manifestations, indicating that the rate of HD pathogenesis leading to motor diagnosis is determined by a completely dominant action of the longest expanded allele and as yet unidentified genetic or environmental factors. Copyright © 2012 by AAN Enterprises, Inc

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure