title: Asymmetric polymicrogyria and periventricular nodular heterotopia due to mutation in ARX.
abstract: Mutations in the ARX gene, at Xp22.3, cause several disorders, including infantile spasms, X-linked lissencephaly with abnormal genitalia (XLAG), callosal agenesis and isolated intellectual disability. Genotype/phenotype studies suggested that polyalanine tract expansion is associated with non-malformative phenotypes, while missense and nonsense mutations cause cerebral malformations, however, patients with structural normal brain and missense mutations have been reported. We report on a male patient born with cleft lip and palate who presented with infantile spasms and hemiplegia. MRI showed agenesis of corpus callosum (ACC), an interhemispheric cyst, periventricular nodular heterotopia (PVNH), and extensive left frontal polymicrogyria (PMG). Sequencing of the ARX gene in the patient identified a six basepair insertion (c.335ins6, exon 2). The insertion leads to a two-residue expansion of the first polyalanine tract and was described previously in a family with non-syndromic X-linked mental retardation. To our knowledge, ARX mutation causing PMG and PVNH is unique, but the spasms and ACC are common in ARX mutations. Clinicians should be aware of the broad clinical range of ARX mutations, and further studies are necessary to investigate the association with PMG and PVNH and to identify possible modifying factors.
authors.affiliation: Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Renske
authors.initials: R
authors.lastname: Oegema
authors.forename: Anneke
authors.initials: A
authors.lastname: Maat-Kievit
authors.forename: Maarten H
authors.initials: MH
authors.lastname: Lequin
authors.forename: Rachel
authors.initials: R
authors.lastname: Schot
authors.forename: Veerle M H
authors.initials: VM
authors.lastname: Nanninga-van den Neste
authors.forename: Marianne E
authors.initials: ME
authors.lastname: Doornbos
authors.forename: Marie C Y
authors.initials: MC
authors.lastname: de Wit
authors.forename: Dicky J
authors.initials: DJ
authors.lastname: Halley
authors.forename: Grazia M S
authors.initials: GM
authors.lastname: Mancini
mesh_terms: D019066:Facies; D006579:Heterozygote; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007223:Infant; D059785:Karyotype; D008297:Male; D054220:Malformations of Cortical Development / Q000175:diagnosis / Q000235:genetics*; D016254:Mutagenesis, Insertional; D009154:Mutation; D059906:Neuroimaging; D054091:Periventricular Nodular Heterotopia / Q000175:diagnosis / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
chemical_list: C469264:ARX protein, human; D018398:Homeodomain Proteins; D014157:Transcription Factors