What causes motor neuron diseases?

Motor neuron diseases (MNDs) are the result of problems with communication between motor neurons (nerves) and muscles. Normally, nerves in the brain send commands to muscle nerve cells to carry out specific movements. When nerve cells along this chain of command are damaged or destroyed by motor neuron disease, they cannot receive the brain’s messages. This leads to the symptoms of motor neuron diseases, such as muscle weakening and wasting, fasciculations (uncontrollable twitching), spasticity, and stiffness in the legs and arms.

It is not known what causes the destruction of motor neurons in motor neuron disease; however, some cases of MNDs are inherited and run in families. Some inherited forms of amyotrophic lateral sclerosis (ALS) are caused by mutations in the SOD1 gene, which helps protect your body’s cells from oxidative damage.

Currently, researchers are investigating factors that may be related to the development of MNDs, such as ALS. These factors include:

  • Abnormally high levels of glutamate, a chemical that passes messages between nerves

  • Defective immune response in which the immune system may attack the nerves that control muscles, leading to a loss of muscle control

  • Environmental factors, such as infections, toxic substances, and dietary deficiencies

What are the risk factors for motor neuron diseases?

A few factors increase the risk of developing a motor neuron disease (MND). They include:

  • Age older than 50 years

  • Family history of MND

  • Male gender

  • Personal history of MND; for example, if you have primary lateral sclerosis, you are more likely to develop ALS


What are motor neuron diseases?

Motor neuron diseases (MNDs) are a group of neurological conditions that progressively destroy motor neuron cells. Motor neuron cells are critical to health and normal, everyday functioning because they control many voluntary muscle actions, such as swallowing, breathing, speaking, talking, hand gestures, and walking. This is different from sensory nerves that permit you to sense touch, pain an... Read more about motor neuron diseasesintroduction


What are the symptoms of motor neuron diseases?

Symptoms of motor neuron disease (MND) are related to problems with communication between your nerves and muscles. Symptoms of motor neuron diseases vary depending on the specific disease.

Early symptoms of MNDs

You may experience symptoms daily or just once in a while. In the early stages of disease, symptoms may be subtle and include:


How are motor neuron diseases treated?

While there is no cure for motor neuron diseases (MNDs), some drug treatments can help reduce the severity of symptoms. One drug, riluzole (Rilutek), may help slow damage to the nerves that control muscles. Other treatments and medical support, such as physical therapy, speech therapy, assisted breathing apparatuses, and home hospice care, are aimed at helping you and your family cope with the ... Read more about motor neuron diseasestreatments

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Sep 6, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Brain and Nerves