CausesBy Mayo Clinic staff
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, on the other hand, has an identifiable cause: mutations in a gene called ALS2. Although researchers don't completely understand how it causes the disease, they know that the ALS2 gene is responsible for providing instructions for making a protein called alsin, which is abundant in motor neuron cells. When the instructions are altered in someone with juvenile PLS, the protein alsin becomes unstable and doesn't function 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.
- 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 Aug. 17, 2010.
- Juvenile primary lateral sclerosis. National Institutes of Health Genetics Home Reference. http://ghr.nlm.nih.gov/condition=juvenileprimarylateralsclerosis. Accessed Aug. 16, 2010.
- Murray B, et al. Disorders of upper and lower motor neurons. In: Bradley WG, et al. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa.: Butterworth-Heinemann Elsevier; 2008. http://www.mdconsult.com/book/player/book.do?method=display&type=bookPage&decorator=header&eid=4-u1.0-B978-0-7506-7525-3..50116-3&displayedEid=4-u1.0-B978-0-7506-7525-3..50116-3--cesec19&uniq=215117994&isbn=978-0-7506-7525-3&sid=1040472768. Accessed Aug. 16, 2010.
- Brugman F, et al. Adult-onset primary lateral sclerosis is not associated with mutations in the ALS2 gene. Neurology. 2007;69:702.
- Tartaglia MC, et al. Differentiation between primary lateral sclerosis and amyotrophic lateral sclerosis: Examination of symptoms and signs at disease onset and during follow-up. Archives of Neurology. 2007;64:232.
- Gordon PH, et al. Clinical features that distinguish PLS, upper motor neuron-dominant ALS, and typical ALS. Neurology. 2009;72:1948.
- Hadano S, et al. Molecular and cellular function of ALS2/alsin: Implication of membrane dynamics in neuronal development and degeneration. Neurochemistry International. 2007;51:74.
- Motor neuron diseases fact sheet. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/motor_neuron_diseases/detail_motor_neuron_diseases.htm. Accessed Aug. 17, 2010.