Association of a Locus in the<i>CAMTA1</i>Gene With Survival in Patients With Sporadic Amyotrophic Lateral Sclerosis
Authors: Isabella Fogh, Kuang Lin, Cinzia Tiloca, James Rooney, Cinzia Gellera, Frank P. Diekstra, Antonia Ratti, Aleksey Shatunov, Michael A. van Es, Petroula Proitsi, Ashley Jones, William Sproviero, Adriano Chiò, Russell Lewis McLaughlin, Gianni Sorarù, Lucia Corrado, Daniel Stahl, Roberto Del Bo, Cristina Cereda, Barbara Castellotti, Jonathan D. Glass, Steven Newhouse, Richard Dobson, Bradley N. Smith, Simon Topp, Wouter van Rheenen, Vincent Meininger, Judith Melki, Karen E. Morrison, Pamela J. Shaw, P. Nigel Leigh, Peter M. Andersen, Giacomo P. Comi, Nicola Ticozzi, Letizia Mazzini, Sandra D’Alfonso, Bryan J. Traynor, Philip Van Damme, Wim Robberecht, Robert H. Brown, John E. Landers, Orla Hardiman, Cathryn M. Lewis, Leonard H. van den Berg, Christopher E. Shaw, Jan H. Veldink, Vincenzo Silani, Ammar Al-Chalabi, John Powell
Journal: JAMA Neurology (2016)

<h3>Importance</h3> Amyotrophic lateral sclerosis (ALS) is a devastating adult-onset neurodegenerative disorder with a poor prognosis and a median survival of 3 years. However, a significant proportion of patients survive more than 10 years from symptom onset. <h3>Objective</h3> To identify gene variants influencing survival in ALS. <h3>Design, Setting, and Participants</h3> This genome-wide association study (GWAS) analyzed survival in data sets from several European countries and the United States that were collected by the Italian Consortium for the Genetics of ALS and the International Consortium on Amyotrophic Lateral Sclerosis Genetics. The study population included 4256 patients with ALS (3125 [73.4%] deceased) with genotype data extended to 7 174 392 variants by imputation analysis. Samples of DNA were collected from January 1, 1993, to December 31, 2009, and analyzed from March 1, 2014, to February 28, 2015. <h3>Main Outcomes and Measures</h3> Cox proportional hazards regression under an additive model with adjustment for age at onset, sex, and the first 4 principal components of ancestry, followed by meta-analysis, were used to analyze data. Survival distributions for the most associated genetic variants were assessed by Kaplan-Meier analysis. <h3>Results</h3> Among the 4256 patients included in the analysis (2589 male [60.8%] and 1667 female [39.2%]; mean [SD] age at onset, 59 [12] years), the following 2 novel loci were significantly associated with ALS survival: at 10q23 (rs139550538;<i>P</i> = 1.87 × 10<sup>−9</sup>) and in the<i>CAMTA1</i>gene at 1p36 (rs2412208,<i>P</i> = 3.53 × 10<sup>−8</sup>). At locus 10q23, the adjusted hazard ratio for patients with thers139550538AA or AT genotype was 1.61 (95% CI, 1.38-1.89;<i>P</i> = 1.87 × 10<sup>−9</sup>), corresponding to an 8-month reduction in survival compared with TT carriers. Forrs2412208<i> CAMTA1</i>, the adjusted hazard ratio for patients with the GG or GT genotype was 1.17 (95% CI, 1.11-1.24;<i>P</i> = 3.53 × 10<sup>−8</sup>), corresponding to a 4-month reduction in survival compared with TT carriers. <h3>Conclusions and Relevance</h3> This GWAS robustly identified 2 loci at genome-wide levels of significance that influence survival in patients with ALS. Because ALS is a rare disease and prevention is not feasible, treatment that modifies survival is the most realistic strategy. Therefore, identification of modifier genes that might influence ALS survival could improve the understanding of the biology of the disease and suggest biological targets for pharmaceutical intervention. In addition, genetic risk scores for survival could be used as an adjunct to clinical trials to account for the genetic contribution to survival.