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
- pyramidal disease
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.
Traditionally divided into two sub types
- connatal: more rare and severe 5
Non specific and may show hypoattenuating white matter with progressive white matter atrophy.
- 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
- affected areas often show a reduction in the NAA peak 4
- decreased choline (due to hypomyelination) 4
History and etymology
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).
- 1. Classification of Childhood White Matter Disorders Using Proton MR Spectroscopic Imaging. AJNR Am J Neuroradiol. 2008;29 (7): 1270-1275. AJNR Am J Neuroradiol (full text) - doi:10.3174/ajnr.A1106
- 2. Van der knaap MS, Breiter SN, Naidu S et-al. Defining and categorizing leukoencephalopathies of unknown origin: MR imaging approach. Radiology. 1999;213 (1): 121-33. Radiology (full text) - Pubmed citation
- 3. Takanashi J, Sugita K, Osaka H et-al. Proton MR spectroscopy in Pelizaeus-Merzbacher disease. AJNR Am J Neuroradiol. 1997;18 (3): 533-5. AJNR Am J Neuroradiol (abstract) - Pubmed citation
- 4. Pizzini F, Fatemi AS, Barker PB et-al. Proton MR spectroscopic imaging in Pelizaeus-Merzbacher disease. AJNR Am J Neuroradiol. 2003;24 (8): 1683-9. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 5. Cheon JE, Kim IO, Hwang YS et-al. Leukodystrophy in children: a pictorial review of MR imaging features. Radiographics. 22 (3): 461-76. Radiographics (full text) - Pubmed citation