1 Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.
2 Department of Pathology & Cell Biology and Neurology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States.
3 Department of Molecular, Cellular and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, United States.