title: Expansion of the first polyalanine tract of the ARX gene in a boy presenting with generalized dystonia in the absence of infantile spasms.
abstract: Mutations in the Aristaless-related homeobox (ARX) gene are associated with pleiotropic phenotypes including infantile spasms, mental retardation and dystonia. However, relatively consistent genotype-phenotype correlations have been emphasized in prior reports. We report a boy presenting with mental retardation, tonic seizures and dystonia but without infantile spasms. Gene sequencing detected an additional seven GCG repeats in the first polyalanine tract of the ARX gene, a mutation which leads to an expansion of the normal 16 alanine residues to 23. The same ARX gene mutation has been reported in patients with infantile spasms, but was absent in the present case. This finding highlights the diverse phenotypic spectrum that may result from ARX gene mutations.
authors.affiliation: Department of Child Neurology, National Center Hospital for Mental, Nervous and Muscular Disorders, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-cho, Kodaira, Japan. yshino@ncnp.go.jp
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shinozaki
authors.forename: Maki
authors.initials: M
authors.lastname: Osawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakuma
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Komaki
authors.forename: Eiji
authors.initials: E
authors.lastname: Nakagawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugai
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sasaki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Goto
mesh_terms: D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D042622:DNA Repeat Expansion / Q000235:genetics*; D020821:Dystonic Disorders / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D004827:Epilepsy / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009154:Mutation / Q000235:genetics; D010455:Peptides / Q000235:genetics; D010641:Phenotype; D013036:Spasms, Infantile / Q000235:genetics / Q000503:physiopathology; D014157:Transcription Factors / Q000235:genetics*
chemical_list: C469264:ARX protein, human; D005819:Genetic Markers; D018398:Homeodomain Proteins; D010455:Peptides; D014157:Transcription Factors; C019529:polyalanine