What is ALS?

What is Amyotrophic Lateral Sclerosis?

Most Americans had probably never heard of amyotrophic lateral sclerosis (ALS) before Lou Gehrig, and even now, most people are not aware of what a diagnosis of ALS truly means until an individual or family member is affected.

Motor neuron disorders, including ALS, were starting to be recognized nearly a century before Lou Gehrig developed his first symptoms. Case reports describing the clinical motor neuron syndromes of progressive muscular atrophy, primary lateral sclerosis, progressive bulbar palsy, and “classic” ALS began to appear in the French and British medical literature in the 1830s.

In 1874 a French physician, Jean Martin Charcot, who is regarded as the founder of modern neurology, established the clinical and pathologic characteristics of ALS. His descriptions of ALS remain amazingly accurate to this day, and as a result ALS is referred to as Charcot’s disease in some parts of the world. Americans are familiar with the terms Lou Gehrig’s disease and ALS and know that it is a devastating, uniformly fatal disease.

ALS belongs to a family of inherited and acquired disorders that, together, constitute the motor neuron diseases. Motor neurons are those cells in the brain, brain stem, and spinal cord that control the voluntary movements of muscles, and in motor neuron diseases, damage to these cells causes weakness and sometimes, total paralysis and death.

In most cases of ALS, called sporadic ALS (SALS), motor neurons degenerate and die prematurely of unknown causes. However, in roughly 10% of ALS, the disease is inherited and is called familial ALS (FALS); for some with FALS the causative genetic mutation can be identified, but for others the genetic defects remain unknown.