Overview

Primary lateral sclerosis is a type of motor neuron disease that causes muscle nerve cells to slowly break down, causing weakness. Primary lateral sclerosis (PLS) causes weakness in your voluntary muscles, such as those you use to control your legs, arms and tongue.

Primary lateral sclerosis can happen at any age, but it usually occurs between ages 40 and 60. A subtype of primary lateral sclerosis, known as juvenile primary lateral sclerosis, begins in early childhood and is caused by an abnormal gene passed from parents to children.

Primary lateral sclerosis is often mistaken for another, more common motor neuron disease called amyotrophic lateral sclerosis (ALS). However, primary lateral sclerosis progresses more slowly than ALS, and in most cases isn't fatal.

Oct. 19, 2016
References
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  3. Elman LB, et al. Clinical features of amyotrophic lateral sclerosis and other forms of motor neuron disease. http://www.uptodate.com/home. Accessed June 1, 2013.
  4. NINDS primary lateral sclerosis information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/primary_lateral_sclerosis/primary_lateral_sclerosis.htm. Accessed June 1, 2016.
  5. Tomik B, et al. Pure primary lateral sclerosis – Case reports. Clinical Neurology and Neurosurgery. 2008;110:387.
  6. Juvenile primary lateral sclerosis. Genetics Home Reference. https://ghr.nlm.nih.gov/condition/juvenile-primary-lateral-sclerosis. Accessed June 1, 2016.
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  8. NINDS Motor neuron diseases information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/motor_neuron_diseases/motor_neuron_diseases.htm. Accessed June 1, 2016.