Footnotes

• Contributors GM and YN contributed equally in the conception of the manuscript, the acquisition of the data and drafting of a significant portion of the manuscript, tables and figures. JAC contributed in drafting and editing a significant portion of the manuscript. SS contributed in the analysis of the data and drafting a significant portion of the manuscript and tables. All authors approved the final manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests GM received fellowship funding from the National Multiple Sclerosis Society Institutional Clinician Training Award ICT 0002 and Biogen Fellowship Grant 6873-P-FEL. SS has nothing to disclose. JAC received personal fees for consulting for Adamas, Alkermes, Convelo, EMD Serono, Novartis and Pendopharm; speaking for Mylan and Synthon; and serving as a Co-Editor of Multiple Sclerosis Journal—Experimental, Translational and Clinical. YN received speech honoraria from Actelion and Orphan Europe, and received travel funding from Actelion, Shire and Genzyme.

• Patient consent Obtained.

• Provenance and peer review Not commissioned; externally peer reviewed.