title: Dopa-responsive dystonia: functional analysis of single nucleotide substitutions within the 5' untranslated GCH1 region.
abstract: BACKGROUND
  Mutations in the GCH1 gene are associated with childhood onset, dopa-responsive dystonia (DRD). Correct diagnosis of DRD is crucial, given the potential for complete recovery once treated with L-dopa. The majority of DRD associated mutations lie within the coding region of the GCH1 gene, but three additional single nucleotide sequence substitutions have been reported within the 5' untranslated (5'UTR) region of the mRNA. The biologic significance of these 5'UTR GCH1 sequence substitutions has not been analyzed.
  
  
  RESULTS
  Luciferase reporter assays, quantitative real time PCR and RNA decay assays, combined with bioinformatics, revealed a pathogenic 5'UTR GCH1 substitution. The +142C>T single nucleotide 5'UTR substitution that segregates with affected status in DRD patients, substantially attenuates translation without altering RNA expression levels or stability. The +142C>T substitution disrupts translation most likely by creating an upstream initiation start codon (uAUG) and an upstream open reading frame (uORF).
  
  
  CONCLUSIONS
  This is the first GCH1 regulatory substitution reported to act at a post-transcriptional level, increasing the list of genetic diseases caused by abnormal translation and reaffirming the importance of investigating potential regulatory substitutions in genetic diseases.
authors.affiliation: Department of Neurogenetics, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Ioanna A
authors.initials: IA
authors.lastname: Armata
authors.forename: Leonora
authors.initials: L
authors.lastname: Balaj
authors.forename: John K
authors.initials: JK
authors.lastname: Kuster
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.forename: Shelun
authors.initials: S
authors.lastname: Tsai
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Armatas
authors.forename: Trisha J
authors.initials: TJ
authors.lastname: Multhaupt-Buell
authors.forename: Roy
authors.initials: R
authors.lastname: Soberman
authors.forename: Xandra O
authors.initials: XO
authors.lastname: Breakefield
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ichinose
authors.forename: Nutan
authors.initials: N
authors.lastname: Sharma
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D003062:Codon; D019295:Computational Biology; D020821:Dystonic Disorders / Q000235:genetics*; D006136:GTP Cyclohydrolase / Q000737:chemistry / Q000235:genetics*; D015870:Gene Expression; D017930:Genes, Reporter; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D020641:Polymorphism, Single Nucleotide; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment
chemical_list: D020121:5' Untranslated Regions; D003062:Codon; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D006136:GTP Cyclohydrolase