Article

Neurotoxicity Research

, Volume 19, Issue 1, pp 31-48

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Correlations Between Gene Expression and Mercury Levels in Blood of Boys With and Without Autism

  • Boryana StamovaAffiliated withDepartment of Neurology, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention Email author 
  • , Peter G. GreenAffiliated withDepartment of Civil and Environmental Engineering, University of California at Davis
  • , Yingfang TianAffiliated withDepartment of Neurology, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
  • , Irva Hertz-PicciottoAffiliated withDepartment of Public Health Sciences, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
  • , Isaac N. PessahAffiliated withDepartment of VM: Molecular Biosciences, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
  • , Robin HansenAffiliated withDepartment of Pediatrics, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
  • , Xiaowei YangAffiliated withDepartment of Public Health Sciences, University of California at Davis Medical Center
  • , Jennifer TengAffiliated withDepartment of Neurology, University of California at Davis Medical Center
  • , Jeffrey P. GreggAffiliated withDepartment of Pathology, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
    • , Paul AshwoodAffiliated withDepartment of Medical Microbiology and Immunology, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
    • , Judy Van de WaterAffiliated withDivision of Rheumatology, Allergy and Clinical Immunology, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention
    • , Frank R. SharpAffiliated withDepartment of Neurology, University of California at Davis Medical CenterThe MIND Institute, University of California at Davis Medical CenterUC Davis Center for Children’s Environmental Health and Disease Prevention

Abstract

Gene expression in blood was correlated with mercury levels in blood of 2- to 5-year-old boys with autism (AU) compared to age-matched typically developing (TD) control boys. This was done to address the possibility that the two groups might metabolize toxicants, such as mercury, differently. RNA was isolated from blood and gene expression assessed on whole genome Affymetrix Human U133 expression microarrays. Mercury levels were measured using an inductively coupled plasma mass spectrometer. Analysis of covariance (ANCOVA) was performed and partial correlations between gene expression and mercury levels were calculated, after correcting for age and batch effects. To reduce false positives, only genes shared by the ANCOVA models were analyzed. Of the 26 genes that correlated with mercury levels in both AU and TD boys, 11 were significantly different between the groups (P(Diagnosis*Mercury) ≤ 0.05). The expression of a large number of genes (n = 316) correlated with mercury levels in TD but not in AU boys (P ≤ 0.05), the most represented biological functions being cell death and cell morphology. Expression of 189 genes correlated with mercury levels in AU but not in TD boys (P ≤ 0.05), the most represented biological functions being cell morphology, amino acid metabolism, and antigen presentation. These data and those in our companion study on correlation of gene expression and lead levels show that AU and TD children display different correlations between transcript levels and low levels of mercury and lead. These findings might suggest different genetic transcriptional programs associated with mercury in AU compared to TD children.

Keywords

Blood Mercury Heavy metals Autism Microarrays Genes