Specific Imaging Findings

Hindbrain abnormalities in congenital muscular dystrophies (CMD) comprise a variable association of brainstem and cerebellar hypoplasia and dysplasia. In Walker-Warburg syndrome (WWS), the brainstem shows a typical posterior kink, resulting in a broad inverted S-shape on sagittal MR images; the cerebellum is profoundly hypoplastic, sometimes with a configuration that resembles a Dandy-Walker malformation, and the cerebellar cortex is dysplastic. In both Fukuyama CMD (FCMD) and muscle-eye-brain disease (MEB), the brainstem is hypoplastic, with a marked reduction in size of the pontine protuberance and presence of pontine clefts in MEB; the cerebellum is also hypoplastic, usually with a greater degree of involvement of the vermis than the hemispheres. Furthermore, CSF-isointense microcysts are found in both cerebellar hemispheres in a subcortical location. Supratentorially, the appearance of the cortex ranges from complete lissencephaly in WWS to a variable pachygyric or polymicrogyric irregularly bumpy and knobbed “cobblestone” appearance in FCMD and MEB, which is variably associated with white matter dysmyelination and ventricular enlargement. However, the supratentorial compartment may be completely normal.

Pertinent Clinical Information

Affected patients present with hypotonia, weakness, variably severe congenital joint contractures, and dystrophic changes on muscle biopsy. Serum creatine kinase is moderately elevated. Neurological involvement mainly comprises variably severe psychomotor delay and convulsions. Ocular findings include micro-phthalmia, cataracts, congenital glaucoma, persistent hyperplastic primitive vitreous, retinal detachment, and optic nerve atrophy.