DefinitionBy Mayo Clinic staff
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 is a type of motor neuron disease that causes muscle nerve cells to slowly break down, causing weakness.
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.
- 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 April 23, 2013.
- Daroff RB, et al. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-1-4377-0434-1..C2009-0-40427-6--TOP&isbn=978-1-4377-0434-1&uniqId=364938937-2. Accessed April 29, 2013.
- Singer MA, et al. Primary lateral sclerosis. Muscle and Nerve. 2007;35:291.
- Juvenile primary lateral sclerosis. Genetics Home Reference. http://ghr.nlm.nih.gov/condition/juvenile-primary-lateral-sclerosis/show/. Accessed April 29, 2013.
- Brugman F, et al. Adult-onset primary lateral sclerosis is not associated with mutations in the ALS2 gene. Neurology. 2007;69:702.
- Neurological diagnostic tests and procedures. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/misc/diagnostic_tests.htm. Accessed April 29, 2013.
- Motor neuron diseases fact sheet. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/motor_neuron_diseases/motor_neuron_diseases.htm. Accessed April 23, 2013.
- Almeida V, et al. Primary lateral sclerosis: Predicting functional outcome. Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. 2013;14:141.
- Iwata NK, et al. White matter alterations differ in primary lateral sclerosis and amyotrophic lateral sclerosis. Brain. 2011;134:2642.
- Treatments and therapies. Spastic Paraplegia Foundation Inc. http://sp-foundation.org/understanding-hsp-pls/treatments-and-therapies/. Accessed May 1, 2013.