Browsing by Author "Suchowersky, Oksana"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Genetic Testing in Parkinson's Disease
    (Wiley, 2023) Pal, Gian; Cook, Lola; Schulze, Jeanine; Verbrugge, Jennifer; Alcalay, Roy N.; Merello, Marcelo; Sue, Carolyn M.; Bardien, Soraya; Bonifati, Vincenzo; Chung, Sun Ju; Foroud, Tatiana; Gatto, Emilia; Hall, Anne; Hattori, Nobutaka; Lynch, Tim; Marder, Karen; Mascalzoni, Deborah; Novaković, Ivana; Thaler, Avner; Raymond, Deborah; Salari, Mehri; Shalash, Ali; Suchowersky, Oksana; Mencacci, Niccolò E.; Simuni, Tanya; Saunders-Pullman, Rachel; Klein, Christine; Medical and Molecular Genetics, School of Medicine
    Genetic testing for persons with Parkinson's disease is becoming increasingly common. Significant gains have been made regarding genetic testing methods, and testing is becoming more readily available in clinical, research, and direct-to-consumer settings. Although the potential utility of clinical testing is expanding, there are currently no proven gene-targeted therapies, but clinical trials are underway. Furthermore, genetic testing practices vary widely, as do knowledge and attitudes of relevant stakeholders. The specter of testing mandates financial, ethical, and physician engagement, and there is a need for guidelines to help navigate the myriad of challenges. However, to develop guidelines, gaps and controversies need to be clearly identified and analyzed. To this end, we first reviewed recent literature and subsequently identified gaps and controversies, some of which were partially addressed in the literature, but many of which are not well delineated or researched. Key gaps and controversies include: (1) Is genetic testing appropriate in symptomatic and asymptomatic individuals without medical actionability? (2) How, if at all, should testing vary based on ethnicity? (3) What are the long-term outcomes of consumer- and research-based genetic testing in presymptomatic PD? (4) What resources are needed for clinical genetic testing, and how is this impacted by models of care and cost-benefit considerations? Addressing these issues will help facilitate the development of consensus and guidelines regarding the approach and access to genetic testing and counseling. This is also needed to guide a multidisciplinary approach that accounts for cultural, geographic, and socioeconomic factors in developing testing guidelines.
  • Thumbnail Image
    Item
    Genome-wide significance for a modifier of age at neurological onset in Huntington's Disease at 6q23-24: the HD MAPS study
    (BioMed Central, 2006-08-17) Li, Jian-Liang; Hayden, Michael R.; Warby, Simon C.; Durr, Alexandra; Morrison, Patrick J.; Nance, Martha; Ross, Christopher A.; Margolis, Russell L.; Rosenblatt, Adam; Squitieri, Ferdinando; Frati, Luigi; Gómez-Tortosa, Estrella; Ayuso García, Carmen; Suchowersky, Oksana; Klimek, Mary Lou; Trent, Ronald J.A.; McCusker, Elizabeth; Novelletto, Andrea; Frontali, Marina; Paulsen, Jane S.; Jones, Randi; Ashizawa, Tetsuo; Lazzarini, Alice; Wheeler, Vanessa C.; Prakash, Ranjana; Xu, Gang; Djoussé, Luc; Medicine, School of Medicine
    Background Age at onset of Huntington's disease (HD) is correlated with the size of the abnormal CAG repeat expansion in the HD gene; however, several studies have indicated that other genetic factors also contribute to the variability in HD age at onset. To identify modifier genes, we recently reported a whole-genome scan in a sample of 629 affected sibling pairs from 295 pedigrees, in which six genomic regions provided suggestive evidence for quantitative trait loci (QTL), modifying age at onset in HD. Methods In order to test the replication of this finding, eighteen microsatellite markers, three from each of the six genomic regions, were genotyped in 102 newly recruited sibling pairs from 69 pedigrees, and data were analyzed, using a multipoint linkage variance component method, in the follow-up sample and the combined sample of 352 pedigrees with 753 sibling pairs. Results Suggestive evidence for linkage at 6q23-24 in the follow-up sample (LOD = 1.87, p = 0.002) increased to genome-wide significance for linkage in the combined sample (LOD = 4.05, p = 0.00001), while suggestive evidence for linkage was observed at 18q22, in both the follow-up sample (LOD = 0.79, p = 0.03) and the combined sample (LOD = 1.78, p = 0.002). Epistatic analysis indicated that there is no interaction between 6q23-24 and other loci. Conclusion In this replication study, linkage for modifier of age at onset in HD was confirmed at 6q23-24. Evidence for linkage was also found at 18q22. The demonstration of statistically significant linkage to a potential modifier locus opens the path to location cloning of a gene capable of altering HD pathogenesis, which could provide a validated target for therapeutic development in the human patient.
  • Thumbnail Image
    Item
    International Genetic Testing and Counseling Practices for Parkinson's Disease
    (Wiley, 2023) Saunders-Pullman, Rachel; Raymond, Deborah; Ortega, Roberto A.; Shalash, Ali; Gatto, Emilia; Salari, Mehri; Markgraf, Maggie; Alcalay, Roy N.; Mascalzoni, Deborah; Mencacci, Niccolò E.; Bonifati, Vincenzo; Merello, Marcelo; Chung, Sun Ju; Novakovic, Ivana; Bardien, Soraya; Pal, Gian; Hall, Anne; Hattori, Nobutaka; Lynch, Timothy; Thaler, Avner; Sue, Carolyn M.; Foroud, Tatiana; Verbrugge, Jennifer; Schulze, Jeanine; Cook, Lola; Marder, Karen; Suchowersky, Oksana; Klein, Christine; Simuni, Tatyana; Medical and Molecular Genetics, School of Medicine
    Background: There is growing clinical and research utilization of genetic testing in Parkinson's disease (PD), including direct-to-consumer testing. Objectives: The aim is to determine the international landscape of genetic testing in PD to inform future worldwide recommendations. Methods: A web-based survey assessing current practices, concerns, and barriers to genetic testing and counseling was administered to the International Parkinson and Movement Disorders Society membership. Results: Common hurdles across sites included cost and access to genetic testing, and counseling, as well as education on genetic counseling. Region-dependent differences in access to and availability of testing and counseling were most notable in Africa. High-income countries also demonstrated heterogeneity, with European nations more likely to have genetic testing covered through insurance than Pan-American and Asian countries. Conclusions: This survey highlights not only diversity of barriers in different regions but also the shared and highly actionable needs for improved education and access to genetic counseling and testing for PD worldwide. © 2023 International Parkinson and Movement Disorder Society.
  • Thumbnail Image
    Item
    A randomized, double-blind, placebo-controlled trial of coenzyme Q10 in Huntington disease
    (2017-01) McGarry, Andrew; McDermott, Michael; Kieburtz, Karl; de Blieck, Elisabeth A.; Beal, Flint; Marder, Karen; Ross, Christopher; Shoulson, Ira; Gibert, Peter; Mallonee, William M.; Guttman, Mark; Wojcieszek, Joanne; Kumar, Rajeev; LeDoux, Mark S.; Jenkins, Mary; Rosas, H. Diana; Nance, Martha; Biglan, Kevin; Como, Peter; Dubinsky, Richard M.; Shannon, Kathleen M.; O'Suilleabhain, Padraig; Chou, Kelvin; Walker, Francis; Martin, Wayne; Wheelock, Vicki L.; McCusker, Elizabeth; Jankovic, Joseph; Singer, Carlos; Sanchez-Ramos, Juan; Scott, Burton; Suchowersky, Oksana; Factor, Stewart A.; Higgins, Donald S., Jr.; Molho, Eric; Revilla, Fredy; Caviness, John N.; Friedman, Joseph H.; Perlmutter, Joel S.; Feigin, Andrew; Anderson, Karen; Rodriguez, Ramon; McFarland, Nikolaus R.; Margolis, Russell L.; Farbman, Eric S.; Raymond, Lynn A.; Suski, Valerie; Kostyk, Sandra; Colcher, Amy; Seeberger, Lauren; Epping, Eric; Esmail, Sherali; Diaz, Nancy; Fung, Wai Lun Alan; Diamond, Alan; Frank, Samuel; Hanna, Philip; Hermanowicz, Neal; Dure, Leon S.; Cudkowicz, Merit; Department of Neurology, School of Medicine
    Objective: To test the hypothesis that chronic treatment of early-stage Huntington disease (HD) with high-dose coenzyme Q10 (CoQ) will slow the progressive functional decline of HD. Methods: We performed a multicenter randomized, double-blind, placebo-controlled trial. Patients with early-stage HD (n = 609) were enrolled at 48 sites in the United States, Canada, and Australia from 2008 to 2012. Patients were randomized to receive either CoQ 2,400 mg/d or matching placebo, then followed for 60 months. The primary outcome variable was the change from baseline to month 60 in Total Functional Capacity score (for patients who survived) combined with time to death (for patients who died) analyzed using a joint-rank analysis approach. Results: An interim analysis for futility revealed a conditional power of <5% for the primary analysis, prompting premature conclusion in July 2014. No statistically significant differences were seen between treatment groups for the primary or secondary outcome measures. CoQ was generally safe and well-tolerated throughout the study. Conclusions: These data do not justify use of CoQ as a treatment to slow functional decline in HD.