Pelizaeus-Merzbacher disease

Last revised by Joshua Yap on 13 Jul 2022

Pelizaeus-Merzbacher disease (PMD) is an X-linked leukodystrophy which is characterized by an arrest in myelin development. 

Patients may present with 

  • pendular eye movements (nystagmus)
  • hypotonia
  • pyramidal disease
  • ataxia

Pelizaeus-Merzbacher disease is the result of abnormalities of the proteolipidprotein (PLP1) gene locus at Xq22. This can be either a mutation, deletion or duplication (most common) 4.

Traditionally Pelizaeus-Merzbacher disease has divided into two subtypes:

  • classic 
  • connatal: more rare and severe 5

CT features, as is the case with many leukodystrophies, are non-specific and may show hypoattenuating white matter with progressive white matter atrophy.

Features include:

  • T1: lack of myelination, often seen as low T1 signal regions typically involving internal capsule, proximal corona radiata and the optic radiation
  • T2: near complete absence of expected low signal in the supratentorial region
    • abnormal signal can either be diffuse or patchy
    • if there is patchy involvement, a characteristic tigroid appearance may be seen 5
    • may also show cortical sulcal prominence due to atrophy 4
    • white matter volume may be decreased 4
    • may also involve cerebellum and brainstem 4
  • MR spectroscopy
    • affected areas often show a reduction in the NAA peak 4
    • decreased choline (due to hypomyelination) 4

Named after Friedrich Christoph Pelizaeus (1851-1942), a German neurologist, and Ludwig Merzbacher (1875-1942), an Italian neuropathologist and psychiatrist. 

Although numerous other leukodystrophies are in the general differentials, specific entities to be considered include: 

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Cases and figures

  • Case 1: axial T2 and T1
    Drag here to reorder.
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