title: Correlations of gene expression with ratings of inattention and hyperactivity/impulsivity in Tourette syndrome: a pilot study.
abstract: BACKGROUND
  Inattentiveness, impulsivity and hyperactivity are the primary behaviors associated with attention-deficit hyperactivity disorder (ADHD). Previous studies showed that peripheral blood gene expression signatures can mirror central nervous system disease. Tourette syndrome (TS) is associated with inattention (IA) and hyperactivity/impulsivity (HI) symptoms over 50% of the time. This study determined if gene expression in blood correlated significantly with IA and/or HI rating scale scores in participants with TS.
  
  
  METHODS
  RNA was isolated from the blood of 21 participants with TS, and gene expression measured on Affymetrix human U133 Plus 2.0 arrays. To identify the genes that correlated with Conners' Parents Ratings of IA and HI ratings of symptoms, an analysis of covariance (ANCOVA) was performed, controlling for age, gender and batch.
  
  
  RESULTS
  There were 1201 gene probesets that correlated with IA scales, 1625 that correlated with HI scales, and 262 that correlated with both IA and HI scale scores (P<0.05, |Partial correlation (r(p))|>0.4). Immune, catecholamine and other neurotransmitter pathways were associated with IA and HI behaviors. A number of the identified genes (n=27) have previously been reported in ADHD genetic studies. Many more genes correlated with either IA or HI scales alone compared to those that correlated with both IA and HI scales.
  
  
  CONCLUSIONS
  These findings support the concept that the pathophysiology of ADHD and/or its subtypes in TS may involve the interaction of multiple genes. These preliminary data also suggest gene expression may be useful for studying IA and HI symptoms that relate to ADHD in TS and perhaps non-TS participants. These results will need to be confirmed in future studies.
authors.affiliation: MIND Institute and Department of Neurology, University of California at Davis, Sacramento, CA 95817, USA. tianyf18@gmail.com
authors.forename: Yingfang
authors.initials: Y
authors.lastname: Tian
authors.forename: Boryana
authors.initials: B
authors.lastname: Stamova
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Ander
authors.forename: Glen C
authors.initials: GC
authors.lastname: Jickling
authors.forename: Joan R
authors.initials: JR
authors.lastname: Gunther
authors.forename: Blythe A
authors.initials: BA
authors.lastname: Corbett
authors.forename: Netty G P
authors.initials: NG
authors.lastname: Bos-Veneman
authors.forename: Pieter J
authors.initials: PJ
authors.lastname: Hoekstra
authors.forename: Julie B
authors.initials: JB
authors.lastname: Schweitzer
authors.forename: Frank R
authors.initials: FR
authors.lastname: Sharp
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications* / Q000235:genetics*; D002648:Child; D003710:Demography; D005260:Female; D005786:Gene Expression Regulation; D056726:Genetic Association Studies; D006801:Humans; D007175:Impulsive Behavior / Q000150:complications* / Q000235:genetics; D008297:Male; D010865:Pilot Projects; D011569:Psychiatric Status Rating Scales; D005879:Tourette Syndrome / Q000150:complications* / Q000235:genetics*