Annual severity increment score as a tool for stratifying patients with Niemann-Pick disease type C and for recruitment to clinical trials by Cortina-Borja, M, Vruchte, D, Mengel, E, Amraoui, Y, Imrie, J, Jones, SA, Dali, C, Fineran, P, Kirkegaard, T, Runz, H, Lachman, R, Bremova-Ertl, T, Strupp, M, Platt, FM