title: Paramagnetic signals in the globus pallidus as late radiographic sign of juvenile-onset GM1 gangliosidosis.
abstract: BACKGROUND
  The juvenile form of GM1 gangliosidosis lacks specific physical findings and thus is often a diagnostic challenge for clinicians. T2 hypodensity in the globus pallidus is a characteristic radiographic sign of neurodegeneration with iron accumulation in the brain that is observed in GM1 gangliosidosis, but the exact timing when this radiographic sign becomes apparent remains to be elucidated.
  
  
  METHODS
  Two male siblings had normal development until 2 years of age and then developed psychomotor regression with dystonia. Their neuroimaging studies indicated progressive global cerebral atrophy. Exome sequencing identified compound heterozygous missense mutations in GLB1, leading to a diagnosis of GM1 gangliosidosis.
  
  
  RESULTS
  A retrospective review of neuroimaging studies revealed that the two patients had strikingly similar clinical courses and radiographic progressions with cortical atrophy that preceded the T2 hypointensity in the globus pallidus.
  
  
  CONCLUSIONS
  Paramagnetic signals in the globus pallidus become apparent relatively late during the disease course, once cerebral atrophy has already become prominent. A comprehensive diagnostic approach involving clinical, radiographic, and genetic testing is necessary for the early identification of affected individuals.
authors.affiliation: Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Takenouchi
authors.affiliation: Division of Medical Genetics, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Kosaki
authors.affiliation: Department of Maternal-Fetal Biology, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakabayashi
authors.affiliation: Department of Maternal-Fetal Biology, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Hata
authors.affiliation: Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan. Electronic address: kkosaki@z3.keio.jp.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kosaki
mesh_terms: D002648:Child; D016537:Gangliosidosis, GM1 / Q000150:complications / Q000175:diagnosis*; D005917:Globus Pallidus / Q000000981:diagnostic imaging*; D006801:Humans; D007501:Iron / Q000378:metabolism; D008297:Male; D019636:Neurodegenerative Diseases / Q000209:etiology; D059906:Neuroimaging; D011859:Radiography; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D007501:Iron; D001616:beta-Galactosidase
keywords: GLB1; GM1 gangliosidosis; neurodegeneration with brain iron accumulation; next-generation sequencing