Motor neuron diseases, also known as motor neurone diseases, are a group of disorders that affect the nerve cells that control muscle movement. These diseases are progressive and can lead to weakness, muscle atrophy, and paralysis. Some synonyms for motor neuron diseases include Amyotrophic Lateral Sclerosis (ALS), Lou Gehrig's disease, and Charcot-Marie-Tooth disease. ALS is a specific type of motor neuron disease that affects both upper and lower motor neurons, leading to muscle weakness and wasting. Lou Gehrig's disease is another name for ALS, named after the famous baseball player who was diagnosed with the disease in 1939. Charcot-Marie-Tooth disease is a genetic disorder that affects the peripheral nerves and leads to muscle weakness and loss of sensation in the hands and feet.