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Spastic paraplegia type 7

Reviewed January 2008

What is spastic paraplegia type 7?

Spastic paraplegia type 7 is part of a group of genetic disorders known as hereditary spastic paraplegias. These disorders are characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the lower limbs (paraplegia). Hereditary spastic paraplegias are divided into two types: pure and complex. The pure types involve the lower limbs. The complex types involve the lower limbs and can also affect the upper limbs to a lesser degree; the structure or functioning of the brain; and the nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system). Spastic paraplegia type 7 can occur in either the pure or complex form.

Like all hereditary spastic paraplegias, spastic paraplegia type 7 involves spasticity of the leg muscles and increased muscle weakness. People with this form of spastic paraplegia can also experience exaggerated reflexes (hyperreflexia) in the arms; speech difficulties (dysarthria); difficulty swallowing (dysphagia); involuntary movements of the eyes (nystagmus); mild hearing loss; abnormal curvature of the spine (scoliosis); high-arched feet (pes cavus); numbness, tingling, or pain in the arms and legs (sensory neuropathy); disturbance in the nerves used for muscle movement (motor neuropathy); and muscle wasting (amyotrophy). The onset of symptoms varies greatly among those with spastic paraplegia type 7; however, abnormalities in muscle tone and other features are usually noticeable in adulthood.

How common is spastic paraplegia type 7?

The prevalence of all hereditary spastic paraplegias combined is estimated to be 2 to 6 in 100,000 people worldwide. Spastic paraplegia type 7 likely accounts for only a small percentage of all spastic paraplegia cases.

What genes are related to spastic paraplegia type 7?

Mutations in the SPG7 gene cause spastic paraplegia type 7. The SPG7 gene provides instructions for producing a protein called paraplegin. Located within the inner membrane of the energy-producing centers of cells (mitochondria), paraplegin is one of the proteins that form a complex called the m-AAA protease. The m-AAA protease is responsible for assembling ribosomes (cellular structures that process the cell's genetic instructions to create proteins) and removing nonfunctional proteins in the mitochondria. When there is a mutation in paraplegin, the m-AAA protease cannot function correctly. Nonfunctional m-AAA proteases cause a build up of unusable proteins in the mitochondria of nerve cells, which can result in swelling of the cell, reduced cell signaling, and impaired cell movement, leading to the major signs and symptoms of spastic paraplegia type 7.

How do people inherit spastic paraplegia type 7?

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.

Where can I find information about treatment for spastic paraplegia type 7?

You may find information on treatment or management of spastic paraplegia type 7 or some of its symptoms in the links below, particularly the links for Gene Reviews, Educational resources, and Patient support.

Where can I find additional information about spastic paraplegia type 7?

You may find the following resources about spastic paraplegia type 7 helpful. These materials are written for the general public.

  • MedlinePlus - Health information
    • Health Topic: Neurologic Diseases (http://www.nlm.nih.gov/medlineplus/neurologicdiseases.html)
    • Health Topic: Neuromuscular Disorders (http://www.nlm.nih.gov/medlineplus/neuromusculardisorders.html)
    • Health Topic: Paralysis (http://www.nlm.nih.gov/medlineplus/paralysis.html)
    • Health Topic: Peripheral Nerve Disorders (http://www.nlm.nih.gov/medlineplus/peripheralnervedisorders.html)
  • Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases (http://rarediseases.info.nih.gov/GARD/Disease.aspx?PageID=4&DiseaseID=6637)
  • Additional NIH Resources - National Institutes of Health
    National Institute of Neurological Disorders and Stroke: Hereditary Spastic Paraplegia (http://www.ninds.nih.gov/disorders/hereditary_spastic_paraplegia/hereditary_spastic_paraplegia.htm)
  • Educational resources - Information pages
    • Ask the Geneticist (http://www.genetics.emory.edu/ask/question.php?question_id=2212)
    • Merck Manual of Medical Information, Second Home Edition (http://www.merck.com/mmhe/sec06/ch093/ch093f.html?qt=spastic+paraplegia&alt)
    • Orphanet: Spastic paraplegia, familial (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=685)
  • Patient support - For patients and families
    • Genetic Alliance (http://www.geneticalliance.org/ws_display.asp?filter=infosearch_results&info_keyword=Hereditary+Spastic+Paraplegia&expand=Treatment)
    • National Ataxia Foundation (http://www.ataxia.org/)
    • National Organization for Rare Disorders (http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Paraplegia,+Hereditary+Spastic)
    • Spastic Paraplegia Foundation (http://sp-foundation.org/)
    • WE MOVE (Worldwide Education and Awareness for Movement Disorders) (http://www.wemove.org/hsp/)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

  • Gene Reviews - Clinical summary
    • Gene Review: Hereditary Spastic Paraplegia (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hsp)
    • Gene Review: Spastic Paraplegia 7 (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=spg7)
  • Gene Tests - DNA tests ordered by healthcare professionals (http://www.genetests.org/query?testid=53873)
  • ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/search/condition=%22spastic+paraplegia+type+7%22+OR+%22Spastic+Paraplegia%2C+Hereditary%22+OR+%22Spastic+Paraplegia%22)
  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=PubMed&term=(SPG7[TIAB])+AND+english[la]+AND+human[mh]&orig_db=PubMed&filters=ON&pmfilter_EDatLimit=360+Days)
  • OMIM - Genetic disorder catalog (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=607259)

What other names do people use for spastic paraplegia type 7?

  • Autosomal Recessive Hereditary Spastic Paraplegia
  • Hereditary Spastic Paraplegia
  • hereditary spastic paraplegia, paraplegin type
  • spastic paraplegia 7

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about spastic paraplegia type 7?

  • See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
  • Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).
  • Submit your question to Ask the Geneticist (http://www.askthegen.org/).

What glossary definitions help with understanding spastic paraplegia type 7?

autosomal ; autosomal recessive ; cell ; deficiency ; difficulty swallowing ; dysarthria ; dysphagia ; gene ; involuntary ; mitochondria ; motor ; muscle tone ; mutation ; nerve cell ; nervous system ; neuropathy ; nystagmus ; oxidative phosphorylation ; paraplegia ; peripheral ; peripheral nervous system ; pes cavus ; phosphorylation ; prevalence ; protease ; protein ; recessive ; reflex ; ribosomes ; scoliosis ; sensory cells ; sensory neuropathy ; sign ; spasticity ; symptom ; wasting

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References
  • Atorino L, Silvestri L, Koppen M, Cassina L, Ballabio A, Marconi R, Langer T, Casari G. Loss of m-AAA protease in mitochondria causes complex I deficiency and increased sensitivity to oxidative stress in hereditary spastic paraplegia. J Cell Biol. 2003 Nov 24;163(4):777-87. Epub 2003 Nov 17. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=14623864)
  • Elleuch N, Depienne C, Benomar A, Hernandez AM, Ferrer X, Fontaine B, Grid D, Tallaksen CM, Zemmouri R, Stevanin G, Durr A, Brice A. Mutation analysis of the paraplegin gene (SPG7) in patients with hereditary spastic paraplegia. Neurology. 2006 Mar 14;66(5):654-9. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=16534102)
  • McDermott CJ, Dayaratne RK, Tomkins J, Lusher ME, Lindsey JC, Johnson MA, Casari G, Turnbull DM, Bushby K, Shaw PJ. Paraplegin gene analysis in hereditary spastic paraparesis (HSP) pedigrees in northeast England. Neurology. 2001 Feb 27;56(4):467-71. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=11222789)
  • Reid E. Science in motion: common molecular pathological themes emerge in the hereditary spastic paraplegias. J Med Genet. 2003 Feb;40(2):81-6. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=12566514)
  • Rugarli EI, Langer T. Translating m-AAA protease function in mitochondria to hereditary spastic paraplegia. Trends Mol Med. 2006 Jun;12(6):262-9. Epub 2006 May 2. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=16647881)
  • Warnecke T, Duning T, Schwan A, Lohmann H, Epplen JT, Young P. A novel form of autosomal recessive hereditary spastic paraplegia caused by a new SPG7 mutation. Neurology. 2007 Jul 24;69(4):368-75. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=17646629)
  • Wilkinson PA, Crosby AH, Turner C, Bradley LJ, Ginsberg L, Wood NW, Schapira AH, Warner TT. A clinical, genetic and biochemical study of SPG7 mutations in hereditary spastic paraplegia. Brain. 2004 May;127(Pt 5):973-80. Epub 2004 Feb 25. Erratum in: Brain. 2004 Sep;127(Pt 9):2148. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=14985266)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: January 2008
Published: May 11, 2009