Megalencephaly, polymicrogyria and ribbon-like band heterotopia: A new cortical malformation
Yu Kobayashi1, Shinichi Magara1, Kenichi Okazaki1
1Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan.
Abstract:
Megalencephalic polymicrogyria syndromes include megalencephaly-capillary malformation and megalencephaly-polymicrogyria-polydactyly-hydrocephalus. Recent genetic studies have identified that genes in the PI3K-AKT pathway are involved in the pathogenesis of these disorders. Herein, we report a patient who presented with developmental delay, epilepsy and peculiar neuroimaging findings of megalencephaly, polymicrogyria, and symmetrical band heterotopia in the periventricular region. The heterotopias exhibited inhomogeneous signals with undulatory mixtures of gray and white matter, resembling ribbon-like heterotopia, with a predominance in the temporal to occipital regions. These neuroradiological findings were not consistent with those in known megalencephalic polymicrogyria syndromes. No genetic abnormality was identified through whole-exome sequencing. The neuroimaging findings of this patient may represent a novel cortical malformation involving megalencephaly with polymicrogyria and ribbon-like band heterotopia.
Insights
This study describes a unique case of megalencephaly with polymicrogyria and ribbon-like heterotopia, presenting novel neuroimaging findings not matching known syndromes. Genetic analysis did not reveal abnormalities, suggesting a potentially new cortical malformation.
Area of Science:
- Neuroscience
- Genetics
- Developmental Biology
Background:
- Megalencephalic polymicrogyria syndromes are rare neurological disorders.
- Genes in the PI3K-AKT pathway are implicated in the pathogenesis of these conditions.
- Existing syndromes include megalencephaly-capillary malformation and megalencephaly-polymicrogyria-polydactyly-hydrocephalus.
Observation:
- A patient presented with developmental delay, epilepsy, and unusual brain imaging results.
- Neuroimaging revealed megalencephaly, polymicrogyria, and symmetrical periventricular band heterotopia.
- The heterotopia showed mixed gray and white matter signals, resembling ribbon-like structures, predominantly in temporal to occipital regions.
Findings:
- The patient's neuroradiological findings were inconsistent with established megalencephalic polymicrogyria syndromes.
- Whole-exome sequencing did not identify any genetic abnormalities.
- The observed combination of megalencephaly, polymicrogyria, and ribbon-like band heterotopia may represent a novel cortical malformation.
Implications:
- This case expands the spectrum of known cortical malformations.
- Further research is needed to elucidate the genetic and molecular basis of this condition.
- Understanding this novel malformation could lead to improved diagnostic approaches and potential therapeutic targets for related disorders.
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