Lou Gehrig's disease, or amyotrophic lateral sclerosis (ALS), has no cure. It causes motor neurons in the central nervous system to shrink, resulting in severe muscle paralysis. ALS patients typically die within three to five years of diagnosis.

Scientists cannot access the failing motor neurons inside ALS patients to understand how the disease damages these nerve cells. However, a team of researchers from Harvard and Columbia universities have used a recently developed stem cell technique to generate unlimited quantities of motor neurons in the laboratory from the skin cells of two elderly ALS patients. This is the first disease-specific stem cell line ever created. Scientists now aim to use the ALS-affected motor neurons for research and treatment of the disease.