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Spinal muscular atrophy with progressive myoclonic epilepsy
Spinal muscular atrophy with progressive myoclonic epilepsy
Other names	Hereditary myoclonus-progressive distal muscular atrophy syndrome
	This condition is inherited in an autosomal recessive manner
Specialty	Neurology

Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME), sometimes called Jankovic–Rivera syndrome, is a very rare neurodegenerative disease whose symptoms include slowly progressive muscle loss (atrophy), predominantly affecting proximal muscles, combined with denervation and myoclonic seizures.^[1] Only 12 known human families are described in scientific literature to have SMA-PME.^[2]

SMA-PME is associated with a missense mutation (c.125C→T) or deletion in exon 2 of the ASAH1 gene and is inherited in an autosomal recessive manner.^[3] SMA-PME is closely related to a lysosomal disorder disease called Farber lipogranulomatosis.^[4] As with many genetic disorders, there is no known cure for SMA-PME.

The condition was first described in 1979 by American researchers Joseph Jankovic and Victor M. Rivera.^[5]

ASAH1 gene

The ASAH1 gene codes for acid ceramidase, an enzyme found in lysosomes. The lysosome breaks down acid ceramidase; the fatty acid component ^[6] is then used to produce myelin. Myelin is an insulating coating around the neurons in the body which helps to contain bioelectrical signals along a nerve cell's axon and increase transmission rate.^[7] In patients with SMA-PME, the ceramidase function decreases to 33.33% effective.^[2] The lack of myelin resulting from the lack of acid ceramidase breakdown leads to nerve cell dysfunction.^{[citation needed]}

References

^ Haliloglu, G.; Chattopadhyay, A.; Skorodis, L.; Manzur, A.; Mercuri, E.; Talim, B.; Akçören, Z.; Renda, Y.; Muntoni, F.; Topaloğlu, H. (2002). "Spinal Muscular Atrophy with Progressive Myoclonic Epilepsy: Report of New Cases and Review of the Literature". Neuropediatrics. 33 (6): 314–319. doi:10.1055/s-2002-37087. PMID 12571787.
^ ^a ^b Reference, Genetics Home. "Spinal muscular atrophy with progressive myoclonic epilepsy". Genetics Home Reference. Retrieved 2018-09-24.
^ Zhou, J.; Tawk, M.; Tiziano, F. D.; Veillet, J.; Bayes, M.; Nolent, F.; Garcia, V.; Servidei, S.; Bertini, E.; Castro-Giner, F.; Renda, Y.; Carpentier, S. P.; Andrieu-Abadie, N.; Gut, I.; Levade, T.; Topaloglu, H.; Melki, J. (2012). "Spinal Muscular Atrophy Associated with Progressive Myoclonic Epilepsy is Caused by Mutations in ASAH1". The American Journal of Human Genetics. 91 (1): 5–14. doi:10.1016/j.ajhg.2012.05.001. PMC 3397266. PMID 22703880.
^ Gan, Joanna J.; Garcia, Virginie; Tian, Jane; Tagliati, Michele; Parisi, Joseph E.; Chung, Jeffrey M.; Lewis, Richard; Baloh, Robert; Levade, Thierry; Pierson, Tyler Mark (2015-12-01). "Acid ceramidase deficiency associated with spinal muscular atrophy with progressive myoclonic epilepsy". Neuromuscular Disorders. 25 (12): 959–963. doi:10.1016/j.nmd.2015.09.007. ISSN 0960-8966. PMID 26526000. S2CID 25574559.
^ Jankovic, J.; Rivera, V. M. (1979). "Hereditary myoclonus and progressive distal muscular atrophy". Annals of Neurology. 6 (3): 227–231. doi:10.1002/ana.410060309. PMID 534421. S2CID 34843480.
^ Park, Jae-Ho; Schuchman, Edward H. (December 2006). "Acid ceramidase and human disease". Biochimica et Biophysica Acta (BBA) - Biomembranes. 1758 (12): 2133–2138. doi:10.1016/j.bbamem.2006.08.019. ISSN 0006-3002. PMID 17064658.
^ Morell, Pierre; Quarles, Richard H. (1999). "The Myelin Sheath". Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th Edition.