Study concept and design: Taylor, Horvath, Chinnery.
Acquisition, analysis, or interpretation of the data: All authors.
Drafting of the manuscript: Taylor, Pyle, Horvath, Chinnery.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Griffin, Santibanez-Koref.
Obtained funding: Taylor, Horvath, Chinnery.
Administrative, technical, or material support: Pyle, Duff, Smertenko, Alston, Neeve, Best, Kirschner, Schara, Talim, Topaloglu, Holinski-Feder, Abicht, Czermin, Kleinle, McFarland.
Study supervision: Taylor, Horvath, Chinnery.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: Drs Taylor, Turnbull, and Chinnery receive support from the Wellcome Trust Centre for Mitochondrial Research (grant 096919Z/11/Z). Drs Taylor, Gorman, Turnbull, McFarland, Horvath, and Chinnery receive support from the UK Medical Research Council Centre for Translational Muscle Diseases (grant G0601943) and Mitochondrial Disease Patient Cohort (grant G0800674). Dr Horvath was supported by the UK Medical Research Council (grant G1000848) and the European Research Council (grant 309548). Dr Chinnery is a Wellcome Trust Senior Fellow in Clinical Science (grant 101876/Z/13/Z), is a UK National Institute for Health Research (NIHR) senior investigator, and receives additional support from EU FP7 TIRCON and the NIHR Newcastle Biomedical Research Centre based at Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University.
Role of the Sponsors: The sponsors 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; or decision to submit the manuscript for publication.
Disclaimer: The views expressed are those of the author(s) and not necessarily those of the National Health Service, the NIHR, or the Department of Health.
Additional Contributions: We thank the clinicians who referred the patients for further investigation.