title: Megalencephaly, polymicrogyria and ribbon-like band heterotopia: A new cortical malformation.
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.
authors.affiliation: Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan. Electronic address: u-kb@masa.go.jp.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Magara
authors.affiliation: Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Okazaki
authors.affiliation: Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Komatsubara
authors.affiliation: Department of Human Genetics, Yokohama City University Graduate School of Medicine, Japan.
authors.forename: Hirotomo
authors.initials: H
authors.lastname: Saitsu
authors.affiliation: Department of Human Genetics, Yokohama City University Graduate School of Medicine, Japan.
authors.forename: Naomichi
authors.initials: N
authors.lastname: Matsumoto
authors.affiliation: Department of Pediatrics, Showa University School of Medicine, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kato
authors.affiliation: Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan; Niigata University Medical and Dental Hospital, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Tohyama
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging*; D054221:Classical Lissencephalies and Subcortical Band Heterotopias / Q000000981:diagnostic imaging* / Q000235:genetics; D005260:Female; D060005:Genotyping Techniques; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D058627:Megalencephaly / Q000000981:diagnostic imaging* / Q000235:genetics; D046228:Microarray Analysis; D065706:Polymicrogyria / Q000000981:diagnostic imaging* / Q000235:genetics
keywords: Cortical malformation; Megalencephaly; Polymicrogyria; Ribbon-like heterotopia; Subcortical heterotopia