Accepted for Publication: January 6, 2014.
Published Online: March 10, 2014. doi:10.1001/jamaneurol.2014.21.
Study concept and design: Kahle, Woolf.
Acquisition of data: Kahle, Khanna.
Analysis and interpretation of data: Kahle, Khanna, Clapham.
Drafting of the manuscript: Kahle, Khanna, Woolf.
Critical revision of the manuscript for important intellectual content: Kahle, Clapham, Woolf.
Study supervision: Clapham.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was supported by the National Institutes of Health (Drs Kahle, Clapham, and Woolf), the Howard Hughes Medical Institute (Dr Clapham), and the Manton Center for Orphan Disease Research (Drs Kahle and Clapham).
Role of the Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.