Amyotrophic Lateral Sclerosis
Amyotrophic Lateral Sclerosis (ALS), is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. It is the best-known of a complex of conditions known as motor neuron diseases. “Lateral” identifies the areas in a person’s spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates it leads to scarring or hardening (“sclerosis”) in the region.
Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With voluntary muscle action progressively affected, people may lose the ability to speak, eat, move, and breathe. The motor nerves that are affected are the motor neurons that provide voluntary movements and muscle control. Examples of voluntary movements are making the effort to reach for a smart phone or step off a curb. These actions are controlled by the muscles in the arms and legs.
There are two different types of ALS, sporadic and familial. Sporadic, which is the most common form of the disease in the U.S., constitutes 90 – 95 percent of all cases. Familial or inherited ALS (FALS) accounts for 5 to 10 percent of all cases in the U.S. In those families, there is a 50% chance each offspring will inherit the gene mutation and may develop the disease.