Declaration of interest
P. A. Lewis serves as a member of the BBSRC pool of experts, and is a member of the Parkinson’s UK Grant Assessment Panel 1, the Scientific Advisory Panel for Ataxia UK and the Research Strategy Committee of the Multiple Sclerosis Society. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.