Stem cell modeling of mitochondrial parkinsonism reveals key functions of OPA1 by Jonikas, M, Madill, M, Mathy, A, Zekoll, T, Zois, C, Wigfield, S, Kurzawa-Akanbi, M, Browne, C, Sims, D, Chinnery, P, Cowley, S, Tofaris, G