The plasma zinc/serum copper ratio as a biomarker in children with autism spectrum disorders

Biomarkers. 2009 May;14(3):171-80. doi: 10.1080/13547500902783747.


The frequency of zinc deficiency, copper toxicity and low zinc/copper in children with autism spectrum disorders (ASDs) may indicate decrement in metallothionein system functioning. A retrospective review of plasma zinc, serum copper and zinc/copper was performed on data from 230 children with autistic disorder, pervasive developmental disorder-NOS and Asperger's syndrome. The entire cohort's mean zinc level was 77.2 microg dl(-1), mean copper level was 131.5 microg dl(-1), and mean Zn/Cu was 0.608, which was below the 0.7 cut-off of the lowest 2.5% of healthy children. The plasma zinc/serum copper ratio may be a biomarker of heavy metal, particularly mercury, toxicity in children with ASDs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asperger Syndrome / blood*
  • Autistic Disorder / blood*
  • Biomarkers / blood*
  • Child
  • Cohort Studies
  • Copper / blood*
  • Humans
  • Retrospective Studies
  • Zinc / blood*


  • Biomarkers
  • Copper
  • Zinc