Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a late‑onset fatal neurodegenerative disease affecting motor neurons characterized by progressive loss of the upper and lower motor neurons (LMNs) at the spinal or bulbar level with an incidence of about 1/100,000. The disease reflecting degeneration of motor neurons in the primary motor cortex, brainstem and spinal cord.

"Amyotrophy" refers to the atrophy of muscle fibers, and is a progressive wasting of muscle which are denervated as their corresponding anterior horn cells degenerate, leading to weakness of affected muscles and visible fasciculations.

"Lateral sclerosis" refers to the hardness of the anterior and lateral corticospinal tracts as motor neurons in these areas degenerate, where gliosis follows degeneration of the corticospinal tracts.

The feature of ALS was first described in 1869 by French neurologist Jean-Martin Charcot. The disease commonly known as Lou Gehrig’s disease became well known in the United States when baseball player Lou Gehrig was diagnosed with the disease in 1939.

Most ALS cases are sporadic, but about 5–10% of ALS is familial, with a Mendelian pattern of inheritance. Both sporadic and familial ALS (FALS) are associated with degeneration of cortical and spinal motor neurons.

Also known as Charcot disease, ALS is one of the five motor neuron disease (MNDs) that affect motor neurons, while the other four knowns as: Primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), progressive bulbar palsy (PBP), and pseudobulbar palsy.
Amyotrophic Lateral Sclerosis