Pelizaeus Merzbacher disease

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

Patients may present with 

  • pendular eye movements
  • hypotonia
  • pyramidal disease
Genetics

It occurs from a derangement in the proteolipidprotein (PLP1) gene locus at Xq22. This can be either a mutation, deletion or duplication (most common) 4.

Sub types

Traditionally divided into two sub types

  • classic 
  • connatal: more rare and severe 5
CT

Non specific and may show hypoattenuating white matter with progressive white matter atrophy.

MRI

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 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. 

  • Pelizaeus-Merzbacher-like disease (mutations of GJA12 at 1q41-q42 or MCT8 at Xq13.2)
  • 18q- deletion (18q22.3 q23)
  • Sialuria also known as Salla disease (SLC17A5 gene at 6q14-q15). 
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Article Information

rID: 7286
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Pelizaeus-Merzbacher disease
  • Pelizaeus-Merzbacher disease (PMD)

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