Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig disease, involves progressive loss of motor neurons (a type of nerve cell controlling muscle movements) in the brain and spinal cord. ALS is a progressive, disabling, and ultimately fatal disease of unknown cause. Walking, speaking, swallowing, breathing, and other basic functions become impaired with time. About 30 000 Americans currently have ALS. The yearly incidence rate is 1 to 2 new cases per 100 000 individuals. The disease is commonly discovered during middle age and affects more men than women. The July 11, 2007, issue of JAMA includes an article discussing the diagnosis of ALS and recommendations for palliative (supportive) care.