Definition
- A heterogeneous group of disorders that primarily affect the white matter of the central nervous system
General
- Vanishing white matter disease
- Megalencephalic leukoencephalopathy with subcortical cysts
- See Myelination diseases
- X-linked adrenoleukodystrophy
- Pelizaeus-Merzbacher disease
Alexander disease
- Aka:
- Fibrinoid leukodystrophy
- Genetic
- Sporadic
- Most of the cases are
- Familial disease rare.
- A heterozygous mutation in the coding region, mapped to chromosome 17q21, of GFAP, an astrocyte-specific intermediate filament protein, is associated with most cases of infantile sporadic onset.
- Pathology
- Accumulation of large numbers of Rosenthal fibers and eosinophilic granular bodies (large accumulations agglomerations of astrocytic processes) in the degenerated (demyelinated) white matter which is a product of GFAP.
- This is on its own a non-specific finding, as they are also seen in slow-growing or benign astrocytomas (e.g. pilocytic astrocytomas).
- Intracellular deposition of Rosenthal fibres may cause abnormal functioning of the oligodendrocytes.
- 2 types
- Infantile/childhood-onset (most common)
- Obstructive hydrocephalus secondary to periaqueductal involvement and swelling of basal ganglia may be seen.
- Juvenile/adult onset (AOAD)
- Prominent bulbar symptoms (dysphagia, dysphonia or dysarthria), sleep disturbance and impairment of autonomic function.
Canavan disease
- AKA
- Spongiform degeneration of white matter
- (Not to be confused with Creutzfeldt-Jakob Disease)
- Aspartoacylase deficiency,
- Accumulation of N-acetylaspartic acid in blood and urine.
- Elevated levels in the brain establish the diagnosis.
- Is a leukodystrophy clinically characterised by
- Megalencephaly
- Severe mental
- Developmental regression around 6 months of age.
- Neurological deficits, and blindness.
- An autosomal recessive disease of infancy
- Prevalent among Ashkenazi Jews.
- Produces symmetrical low attenuation of hemispheric white matter on CT and macrocephaly
Lysosomal storage disease
- Metachromatic leukodystrophy
- Globoid cell leukodystrophy (Krabbe disease)
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