ALS is a devastating neurodegenerative disease with no cure that specifically affect a patient's motor neurons in the brain. A team at Cedars-Sinai is transplanting millions of genetically engineered stem cells into patients with ALS. When transplanted into the patient spinal cord, these cells become astrocytes, the support cells that keep nerve cells functioning. Due to the genetic modifications, the cells also deliver high doses of a growth factor which has been shown to protect nerve cells. The goal of this early stage trial is to test the safety of this astrocyte replacement strategy in ALS patients.