title: Blood gene expression correlated with tic severity in medicated and unmedicated patients with Tourette Syndrome.
abstract: BACKGROUND
  Tourette Syndrome (TS) has been linked to both genetic and environmental factors. Gene-expression studies provide valuable insight into the causes of TS; however, many studies of gene expression in TS do not account for the effects of medication.
  
  
  METHODS
  To investigate the effects of medication on gene expression in TS patients, RNA was isolated from the peripheral blood of 20 medicated TS subjects (MED) and 23 unmedicated TS subjects (UNMED), and quantified using whole-genome Affymetrix microarrays.
  
  
  RESULTS
  D2 dopamine receptor expression correlated positively with tic severity in MED but not UNMED. GABA(A) receptor ε subunit expression negatively correlated with tic severity in UNMED but not MED. Phenylethanolamine N-methyltransferase expression positively correlated with tic severity in UNMED but not MED.
  
  
  CONCLUSIONS
  Modulation of tics by TS medication is associated with changes in dopamine, norepinephrine and GABA pathways.
authors.affiliation: University of California, Davis, CA 9581, USA. ihliao@ucdavis.edu
authors.forename: Isaac H
authors.initials: IH
authors.lastname: Liao
authors.forename: Blythe A
authors.initials: BA
authors.lastname: Corbett
authors.forename: Donald L
authors.initials: DL
authors.lastname: Gilbert
authors.forename: Silvia A
authors.initials: SA
authors.lastname: Bunge
authors.forename: Frank R
authors.initials: FR
authors.lastname: Sharp
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D002648:Child; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D010625:Phenylethanolamine N-Methyltransferase / Q000235:genetics; D012313:RNA / Q000097:blood* / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000235:genetics; D011963:Receptors, GABA-A / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D020323:Tics / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D005879:Tourette Syndrome / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000235:genetics
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D010625:Phenylethanolamine N-Methyltransferase; D012313:RNA; D017448:Receptors, Dopamine D2; D011963:Receptors, GABA-A; C546274:GABRE protein, human; C481603:NPAS4 protein, human