In primary lateral sclerosis (PLS), nerve cells in the brain that control movement fail over time. This loss causes movement problems, such as slow movements, balance problems and clumsiness.
Adult primary lateral sclerosis
The cause of adult primary lateral sclerosis is unknown. In most cases, it's not an inherited disease, and it's not known why or how it begins.
Juvenile primary lateral sclerosis
Juvenile primary lateral sclerosis is caused by mutations in a gene called ALS2.
Although researchers don't understand how this gene causes the disease, they know that the ALS2 gene is responsible for giving instructions for creating a protein called alsin, which is present in motor neuron cells.
When the instructions are changed in someone with juvenile PLS, the protein alsin becomes unstable and doesn't work properly, which in turn impairs normal muscle function. Adults who get primary lateral sclerosis don't appear to have the same gene mutation.
Juvenile primary lateral sclerosis is an autosomal recessive disease, meaning that both parents have to be carriers of the gene to pass it to their child, even though they don't have the disease themselves.
July 12, 2013
- 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.
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