The fatal neurodegenerative disease ALS, also known as Lou Gehrig's disease, has been under investigation by researchers, and in particular, how it spreads. New findings suggest that transmission can be blocked, and that misfolded non-mutant SOD1 can be transmitted from region to region in the nervous system, offering a molecular explanation for the progressive nature of the spread. ALS is a disease that affects nerve cells in the brain and the spinal cord. There are approximately 140,000 new cases diagnosed worldwide each year.