Background and purpose: Recent work has shown that up to 50% of patients with congenital muscular dystrophies (CMDs) have abnormalities of the brain that can be detected by brain MR imaging. We attempted to determine whether brain MR imaging is useful for the diagnosis and classification of patients with CMDs.
Methods: The brain MR studies of 12 patients with biopsy-proved CMDs were reviewed retrospectively. Using information available in the literature regarding associated brain anomalies as a guide, an attempt was made to classify the patients in terms of "pure" CMD, CMD with occipital agyria, Fukuyama CMD, muscle-eye-brain disease, or Walker-Warburg syndrome.
Results: All the patients were easily classified into one of four groups: pure CMD (four patients), Fukuyama CMD (four patients), muscle-eye-brain disease (two patients), or Walker-Warburg syndrome (two patients). Patients with pure CMD had diffuse central cerebral hypomyelination with mild pontine and cerebellar hypoplasia. Patients with Fukuyama CMD had diffuse central cerebral hypomyelination, cerebellar polymicrogyria (with or without cysts), frontal polymicrogyria, a variable degree of hypoplasia of the pons and cerebellar vermis, and a variable occipital cobblestone cortex. Patients with muscle-eye-brain disease had cerebellar polymicrogyria (with or without cysts), absence of the septum pellucidum, diffuse cerebral cortical dysplasia, pontine and cerebellar vermian hypoplasia, patchy hypomyelination, and variable callosal hypogenesis and hydrocephalus. Patients with Walker-Warburg syndrome had diffuse cerebral cobblestone cortex, absence of cerebral and cerebellar myelin, cerebellar polymicrogyria (with or without cysts), pontine and cerebellar vermal hypoplasia, hydrocephalus, and variable callosal hypogenesis.
Conclusion: MR imaging shows distinctive brain anomalies that allows patients with CMD to be classified into four distinct groups that are consistent with known disorders.