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Canavan disease


Other Names for this Disease
  • ACY2 deficiency
  • Aminoacylase 2 deficiency
  • ASP deficiency
  • ASPA deficiency
  • Aspartoacylase deficiency
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

What is Canavan disease? How does it happen? Can it be treated? What is the prognosis?

Our Answer

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What is Canavan disease?

Canavan disease is an inherited disorder that causes progressive damage to nerve cells in the brain.[1] This disease is one of a group of genetic disorders called leukodystrophies. Leukodystrophies disrupt the growth or maintenance of the myelin sheath, which is the fatty covering that insulates nerve fibers.[1][2] Canavan disease is caused by mutations in the ASPA gene and is inherited in an autosomal recessive pattern.[1][3] While it occurs in people of all ethnic backgrounds, it is most common in people of Ashkenazi (eastern and central European) Jewish heritage, and among Saudi Arabians.[1][2][3]
 
Last updated: 5/14/2015

What are the signs and symptoms of Canavan disease?

The signs and symptoms of Canavan disease usually begin in early infancy; however, the course of the condition can be quite variable. Infants with Canavan disease typically appear normal for the first few months of life. By age 3 to 5 months, affected infants begin having problems with development, including a delay in motor skills such as turning over, controlling head movement, and sitting without support. These infants typically also have weak muscle tone (hypotonia), unusually large head size (macrocephaly), irritability, abnormal posture, and intellectual disability.[1][2] Feeding and swallowing difficulties, seizures, paralysis, blindness, hearing loss, and sleep disturbances may also develop.[1][2][3] Children are characteristically quiet and apathetic.[2] 
Last updated: 5/14/2015

What causes Canavan disease?

Mutations in the ASPA gene cause Canavan disease. The ASPA gene provides instructions for making an enzyme called aspartoacylase. This enzyme normally breaks down a compound called N-acetyl-L-aspartic acid (NAA), which is predominantly found in nerve cells in the brain. The precise function of NAA is unclear. At one time, NAA was thought to have a role in the production of the myelin sheath. Now it seems that this enzyme may be involved in the transport of water molecules out of neurons .[1]

Mutations in the ASPA gene reduce the function of aspartoacylase, which prevents the normal breakdown of NAA. An excess of NAA in the brain is associated with the signs and symptoms of Canavan disease. Studies suggest that if NAA is not broken down properly, the resulting chemical imbalance may interfere with the formation of myelin as the nervous system develops. A buildup of NAA also leads to the progressive destruction of existing myelin around nerve cells. Nerve fibers without this protective covering malfunction which disrupts normal brain development.[1]

Last updated: 5/14/2015

Is Canavan disease inherited?

Yes. Canavan disease is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations.[1][3] 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.[1] When both parents are found to carry the Canavan gene mutation, there is a one in four (25%) chance with each pregnancy that the resulting child will be affected with Canavan disease.[2]
Last updated: 5/14/2015

How might Canavan disease be treated?

Canavan disease causes progressive brain atrophy. There is no cure, nor is there a standard course of treatment. Treatment is symptomatic and supportive.[2][3] 

Management may include provision of adequate nutrition and hydration, treatment of infectious diseases, and protection of the airway. Physical therapy may help to minimize contractures and maximize motor abilities and seating posture. Special education programs can enhance communication skills. Seizures are treated with anti-epileptic drugs. Gastrostomy can help to maintain adequate food intake and hydration when swallowing difficulties exist.[4]
Last updated: 5/15/2015

What is the prognosis for individuals with Canavan disease?

The prognosis for Canavan disease is poor.[2] Life expectancy is variable. Some children die in the first few years of life while others may survive into their teens and twenties.[1][2][3][4] Prognosis often depends upon the clinical course of the disease as well as the level of medical care provided.[4]
Last updated: 5/15/2015

References
Other Names for this Disease
  • ACY2 deficiency
  • Aminoacylase 2 deficiency
  • ASP deficiency
  • ASPA deficiency
  • Aspartoacylase deficiency
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.