Canavan disease

Canavan disease, also known as spongiform degeneration of white matter (not to be confused with Creutzfeldt-Jakob Disease), is a leukodystrophy clinically characterised by megalocephaly, severe mental deficits and blindness. 

It is an autosomal recessive disorder due to deficiency of N-acetylaspartoacylase (key enzyme in myelin synthesis), with resultant accumulation of NAA in the brain, plasma, CSF and urine. Although its effects are wide spread, it has a predilection for subcortical U-fibers and Alzheimer type II astrocytes in the gray matter.

Canavan disease is particularly common between Ashkenazi Jewish community. Clinical onset is in infancy with death before 5 years of age, and often before 18 months.


The edematous sponginess of the white matter causes a characteristically low radiographic attenuation on CT so that it stands out in relief from the relatively unaffected gray matter 6.


There is often a large brain (megalencephaly)

There is typically a diffuse bilateral involvement of subcortical U-fibers 2,4:

  • T1: low signal in white matter
  • T2: high signal in white matter
  • MR spectroscopy: markedly elevated NAA and NAA:creatine ratio
    • this can be remembered using the mnemonic CaNAAvan

There is no enhancement of affected regions on either CT or MR.

The condition is fatal with death resulting at 2-5 years and treatment is generally supportive. No effective treatment is yet available.

It was first described in 1931 by Myrtelle Canavan, American neuropathologist (1879-1953). 

Consider other dysmyelinating diseases such as:

Inborn errors of metabolism
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Article Information

rID: 1045
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Canavan's disease
  • Spongiform degeneration of white matter
  • Spongy degeneration of the brain

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Cases and Figures

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    Case 1
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    Case 1: MR spectroscopy
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    Case 2: probable
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