In early October 2009, the FDA approved a clinical trial of fetal spinal neural precursors owned by Neuralstem, Inc. in patients with amyotrophic lateral sclerosis (ALS). Approval was based in part on prior work in the Koliatsos Lab showing that these precursors can differentiate into neurons in the adult spinal cord after injury, and also in mice and rats with transgenic forms of ALS due to disease-causing mutations in the SOD1 gene (Yan et al., Stem Cells 2006; 24:1976 -1985; Xu et al, Transplantation 2006; 82:865-875; Yan et al, PLoS Medicine 2007; 4: 318-332; Yan et al, J Comp Neurol 2009; 514:297-309). These studies have shown that after being transplanted into the spinal cord, these human precursors survive, undergo neuronal differentiation, and engage in local circuit formation with host motor neurons. Koliatsos believes that the therapeutic effect is mediated via motor neuron trophic factors transferred from transplanted cells onto injured motor neurons via synaptic interactions. The recently approved trial is the first one for stem cells in a major neurodegenerative disorder.