Fact-sheet: Lissencephaly
Updated on 03/31/2020 at 8:29 AM
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Definition
This is a group of rare malformations.
- poorly known incidence: 1/100,000.
Abnormality in the appearance of the gyri (= reduced number and relief) associated with an abnormality in the organization of the cortical cell layers:
--> neuronal migration disorder
- several types depending on etiologies and associated abnormalities, two main groups:
* classic Lissencephaly,
* cobblestone Lissencephaly.
Clinical features
Variable clinical presentation:
- feeding and swallowing disorders,
- muscle tone disorders (marked hypotonia at birth),
- seizures,
- psychomotor delay.
Laboratory findings
Molecular/genetic diagnosis: long and complex.
MRI
MRI is the examination of choice for diagnosing Lissencephaly.
- Smooth, thick cortex (5 to 20 mm versus 2.5 to 4 mm) with loss of white matter-gray matter interdigitations,
- complete agyria, pachygyria,
- classic figure-of-8 appearance (replacement of the Sylvian fissure by a depression),
- less pronounced involvement in the temporal regions,
- brainstem often hypoplastic due to atrophy of the corticospinal tracts,
- sometimes: T2 hyperintensity of the white matter related to gliosis, colpocephaly, callosal dysplasia, or periventricular gray matter heterotopia.
Vascular intervention
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Management
Complex management, sometimes near-total dependence of these children.