Accepted for Publication: June 19, 2013.
Published Online: September 30, 2013. doi:10.1001/jamaneurol.2013.3956.
Study concept and design: Wood, Falcone, Van Deerlin, Grossman.
Acquisition of data: Wood, Falcone, Suh, Irwin, Lee, Van Deerlin, Grossman.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Wood, Falcone, Van Deerlin, Grossman.
Critical revision of the manuscript for important intellectual content: Wood, Suh, Irwin, Chen-Plotkin, Lee, Xie, Van Deerlin, Grossman.
Statistical analysis: Wood, Xie, Grossman.
Obtained funding: Van Deerlin, Grossman.
Study supervision: Van Deerlin, Grossman.
Conflict of Interest Disclosures: None reported.
Funding/Support: This research was funded by grants T32-AG00025 (Dr Irwin), AG033101 (Dr Chen-Plotkin), and AG017586, AG032953, AG10124, and NS044266 from the National Institutes of Health, the ALS Association, and the Wyncote Foundation. Dr Irwin is also supported by the Penn Institute for Translational Medicine and Therapeutics fellowship. Dr Chen-Plotkin is also supported by the Burroughs Wellcome Fund and the Doris Duke Clinician Scientist Development Award.
Role of the Sponsor: The funding institutions had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: The following University of Pennsylvania physicians contributed through clinical evaluation and referral of cases: Steven Arnold, MD, Jason Karlawish, MD, Anjan Chatterjee, MD, Geoffrey Aguirre, MD, and Branch Coslett, MD; there was no financial compensation provided. The authors thank the patients and families who made this research possible.