The average life expectancy of someone with amyotrophic lateral sclerosis, or ALS, is typically two to five years after diagnosis. ALS is a progressive disease, with the majority of individuals living three or more years after diagnosis, according to the ALS Association.
ALS is a neurodegenerative disease. It affects the nerve cells in the spinal cord and brain. There are two types of ALS. Sporadic ALS is the most common type of the disease and can affect anyone. Familial ALS is less common, comprising about 5 to 10 percent of cases in the United States. Familial ALS is an inherited disease, states the ALS Association. Symptoms of ALS include difficulty walking, weakness in the legs, feet and hands, slurring speech and muscle cramps, according to Mayo Clinic.