The onset of ALS can begin unassumingly, with a weakening in one hand, one leg or in the tongue. The disease kills the nerve cells that control the muscles. The body becomes increasingly paralyzed, leading eventually to death. To find its cause, Peter Andersen and his research team at Umeå university are now looking deep inside our cells, with the hope of being able to find a gene therapy that will be able to stop this deadly illness. In focus is the SOD1 gene and the results from the team’s mapping of ALS families in the north of Sweden.