Heather Borders, MD
over 6 years ago
Please choose a workflow. A standard workflow allows you to browse the repository with full case detail; the academic workflow allows you to browse the repository with limited case detail revealed. Double click on the images to launch image viewer.
Joseph Junewick, MD FACR
|Diagnostic Category: Metabolic
|Created: over 7 years ago
|Updated: over 7 years ago
2 year old with developmental delay and macrocephaly.
Alexander’s Disease (Fibrinoid Leukodystrophy)
MR – Axial T1, T2 and postgadolinium T1 images demonstrate bifrontal white matter T1 hypointensity and T2 hyperintensity and T1 hyperintensity in the genu of the corpus callosum.
MRS – STEAM imaging demonstrates depressed NAA and elevated choline and myo-inositol peaks.
Typically patients with Alexander’s disease present in the first year of life with progressive psychomotor retardation and macrocephaly. This disease is related to a chromosomal defect at 17q21, a gene encoding for glial fibrillary acidic protein (GFAP). GFAP is a specific for cells of an astroglial lineage. Overexpression leads to cytoplasmic aggregation which disturbs structural proteins and cell functioning.
On MR, the subcortical white matter is affected early. Frontal T1 and T2 prolongation progresses posteriorly. T1 and T2 shortening occurs in the periventricular regions; post-gadolinium enhancement may be seen. The caudate nuclei and anterior putamina are often affected while the globi pallidi and thalami are less often affected. Cysts are common late in the disease.
Juvenile and adult forms of the disease exist and likely are related to a less severe mutation of the GFAP. These forms present with ataxia, bulbar signs, and spasticity and are more slowly progressive.
Barkovich AJ. Pediatric Neuroimaging, 4th Ed. Lippincott, Williams and Wilkins (2005).