Frequency
Infantile-onset ascending hereditary spastic paralysis is a rare disorder, with at least 30 cases reported in the scientific literature.
Causes
Infantile-onset ascending hereditary spastic paralysis is caused by mutations in the ALS2 gene. This gene provides instructions for making the alsin protein. Alsin is produced in a wide range of tissues, with highest amounts in the brain, particularly in motor neurons. Alsin turns on (activates) multiple proteins called GTPases that convert a molecule called GTP into another molecule called GDP. GTPases play important roles in several cell processes. The GTPases that are activated by alsin are involved in the proper placement of the various proteins and fats that make up the cell membrane, the transport of molecules from the cell membrane to the interior of the cell (endocytosis), and the development of specialized structures called axons and dendrites that project from neurons and are essential for the transmission of nerve impulses.
Mutations in the ALS2 gene alter the instructions for making alsin, often resulting in the production of an abnormally short alsin protein that is unstable and rapidly broken down. It is unclear exactly how ALS2 gene mutations cause infantile-onset ascending hereditary spastic paralysis. Research suggests that a lack of alsin and the subsequent loss of GTPase functions, such as endocytosis and the development of axons and dendrites, contribute to the progressive atrophy of motor neurons that is characteristic of this condition.
Inheritance
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Other Names for This Condition
- IAHSP
- Infantile onset ascending spastic paralysis
- Infantile-onset ascending hereditary spastic paraplegia
Additional Information & Resources
Genetic and Rare Diseases Information Center
Patient Support and Advocacy Resources
Clinical Trials
Catalog of Genes and Diseases from OMIM
Scientific Articles on PubMed
References
- Eker HK, Unlu SE, Al-Salmi F, Crosby AH. A novel homozygous mutation in ALS2 gene in four siblings with infantile-onset ascending hereditary spastic paralysis. Eur J Med Genet. 2014 May-Jun;57(6):275-8. doi: 10.1016/j.ejmg.2014.03.006. Epub 2014 Apr 3. Citation on PubMed
- Lesca G, Eymard-Pierre E, Santorelli FM, Cusmai R, Di Capua M, Valente EM, Attia-Sobol J, Plauchu H, Leuzzi V, Ponzone A, Boespflug-Tanguy O, Bertini E. Infantile ascending hereditary spastic paralysis (IAHSP): clinical features in 11 families. Neurology. 2003 Feb 25;60(4):674-82. doi: 10.1212/01.wnl.0000048207.28790.25. Citation on PubMed
- Orrell RW. ALS2-Related Disorder. 2005 Oct 21 [updated 2021 May 13]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025. Available from http://www.ncbi.nlm.nih.gov/books/NBK1243/ Citation on PubMed
- Racis L, Tessa A, Pugliatti M, Storti E, Agnetti V, Santorelli FM. Infantile-onset ascending hereditary spastic paralysis: a case report and brief literature review. Eur J Paediatr Neurol. 2014 Mar;18(2):235-9. doi: 10.1016/j.ejpn.2013.09.009. Epub 2013 Oct 9. Citation on PubMed
- Wakil SM, Ramzan K, Abuthuraya R, Hagos S, Al-Dossari H, Al-Omar R, Murad H, Chedrawi A, Al-Hassnan ZN, Finsterer J, Bohlega S. Infantile-onset ascending hereditary spastic paraplegia with bulbar involvement due to the novel ALS2 mutation c.2761C>T. Gene. 2014 Feb 15;536(1):217-20. doi: 10.1016/j.gene.2013.11.043. Epub 2013 Dec 4. Citation on PubMed
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