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Genetics Home Reference: your guide to understanding genetic conditions
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Spastic paraplegia type 2

Reviewed March 2008

What is spastic paraplegia type 2?

Spastic paraplegia type 2 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 2 can occur in either the pure or complex form.

People with the pure form of spastic paraplegia type 2 experience spasticity in the lower limbs, usually without any additional features. People with the complex form of spastic paraplegia type 2 have lower limb spasticity and can also experience problems with movement and balance (ataxia); involuntary movements of the eyes (nystagmus); mild intellectual disability; involuntary, rhythmic shaking (tremor); and degeneration (atrophy) of the optic nerves, which carry information from the eyes to the brain. Symptoms usually become apparent between the ages of 1 and 5 years; those affected are typically able to walk and have a normal lifespan.

How common is spastic paraplegia type 2?

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

What genes are related to spastic paraplegia type 2?

Mutations in the PLP1 gene cause spastic paraplegia 2. The PLP1 gene provides instructions for producing proteolipid protein 1 and a modified version (isoform) of proteolipid protein 1, called DM20. Proteolipid protein 1 and DM20 are primarily located in the brain and spinal cord (central nervous system) and are the main proteins found in myelin, the fatty covering that insulates nerve fibers. A lack of proteolipid protein 1 and DM20 can cause a reduction in the formation of myelin (dysmyelination) which can impair nervous system function, resulting in the signs and symptoms of spastic paraplegia type 2.

Related Gene(s)

Changes in this gene are associated with spastic paraplegia type 2.

  • PLP1

How do people inherit spastic paraplegia type 2?

This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. Because females have two copies of the X chromosome, one altered copy of the gene in each cell usually leads to less severe symptoms in females than in males, or may cause no symptoms at all. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. She can pass on the gene, but generally does not experience signs and symptoms of the disorder. Some females who carry a PLP1 mutation, however, may experience muscle stiffness and a decrease in intellectual function. Females with one PLP1 mutation have an increased risk of experiencing progressive deterioration of cognitive functions (dementia) later in life.

Where can I find information about diagnosis or management of spastic paraplegia type 2?

These resources address the diagnosis or management of spastic paraplegia type 2 and may include treatment providers.

  • Gene Review: Hereditary Spastic Paraplegia Overview (http://www.ncbi.nlm.nih.gov/books/NBK1509)
  • Gene Review: PLP1-Related Disorders (http://www.ncbi.nlm.nih.gov/books/NBK1182)
  • Genetic Testing Registry: Spastic paraplegia 2 (http://www.ncbi.nlm.nih.gov/gtr/conditions/C1839264)
  • Spastic Paraplegia Foundation, Inc.: Treatments and Therapies (http://sp-foundation.org/understanding-hsp-pls/treatments-and-therapies/)

You might also find information on the diagnosis or management of spastic paraplegia type 2 in Educational resources (http://ghr.nlm.nih.gov/condition/spastic-paraplegia-type-2/show/Educational+resources) and Patient support (http://ghr.nlm.nih.gov/condition/spastic-paraplegia-type-2/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about spastic paraplegia type 2?

You may find the following resources about spastic paraplegia type 2 helpful. These materials are written for the general public.

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

What other names do people use for spastic paraplegia type 2?

  • Hereditary X-linked Recessive Spastic Paraplegia
  • spastic paraplegia 2
  • X linked Recessive Hereditary Spastic Paraplegia

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and 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 2?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding spastic paraplegia type 2?

ataxia ; atrophy ; carrier ; cell ; central nervous system ; chromosome ; dementia ; disability ; gene ; hereditary ; inheritance ; inherited ; involuntary ; leukodystrophy ; mutation ; nervous system ; nystagmus ; paraplegia ; peripheral ; peripheral nervous system ; prevalence ; protein ; recessive ; sensory cells ; sex chromosomes ; spasticity ; tremor ; X-linked recessive

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

References

  • Cailloux F, Gauthier-Barichard F, Mimault C, Isabelle V, Courtois V, Giraud G, Dastugue B, Boespflug-Tanguy O. Genotype-phenotype correlation in inherited brain myelination defects due to proteolipid protein gene mutations. Clinical European Network on Brain Dysmyelinating Disease. Eur J Hum Genet. 2000 Nov;8(11):837-45. (http://www.ncbi.nlm.nih.gov/pubmed/11093273?dopt=Abstract)
  • Hudson LD. Pelizaeus-Merzbacher disease and spastic paraplegia type 2: two faces of myelin loss from mutations in the same gene. J Child Neurol. 2003 Sep;18(9):616-24. Review. (http://www.ncbi.nlm.nih.gov/pubmed/14572140?dopt=Abstract)
  • Inoue K, Tanaka H, Scaglia F, Araki A, Shaffer LG, Lupski JR. Compensating for central nervous system dysmyelination: females with a proteolipid protein gene duplication and sustained clinical improvement. Ann Neurol. 2001 Dec;50(6):747-54. (http://www.ncbi.nlm.nih.gov/pubmed/11761472?dopt=Abstract)
  • Inoue K. PLP1-related inherited dysmyelinating disorders: Pelizaeus-Merzbacher disease and spastic paraplegia type 2. Neurogenetics. 2005 Feb;6(1):1-16. Epub 2004 Dec 31. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15627202?dopt=Abstract)
  • 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/pubmed/12566514?dopt=Abstract)
  • Soderblom C, Blackstone C. Traffic accidents: molecular genetic insights into the pathogenesis of the hereditary spastic paraplegias. Pharmacol Ther. 2006 Jan;109(1-2):42-56. Epub 2005 Jul 7. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16005518?dopt=Abstract)

 

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: March 2008
Published: September 15, 2014