miMNs from control and ALS iPSCs as well as ESCs express known MN markers, including HB9, Islet1 and the cholinergic neuron marker ChAT (Fig. 3A and B; HB9+/TUJ1+: > 92%; Islet1+/TUJ1+: > 70%; ChAT+/TUJ1+: > 97%). The gene discussed is MNX1; the disease is amyotrophic lateral sclerosis.