Porphyrinuria in childhood autistic disorder: implications for environmental toxicity.


Evidence Type: Research (Generic)
Nataf R, Skorupka C, Amet L, Lam A, Springbett A, Lathe R, Porphyrinuria in childhood autistic disorder: implications for environmental toxicity. Toxicol Appl Pharmacol. 2006 Jul 15;214(2):99-108. Epub 2006 Jun 16 - www.ncbi.nlm.nih.gov/pubmed?term=PMID%3A%2016782144%20 Score: 0.0/0.0


This research measures the ratios of two different chemicals (porphyrin and creatinine) in the urine of 269 children, including 106 who were autistic The research found a difference in this ratio in the autistic children, which was "normalized" after giving the children a substance normally used to treat heavy metal poisoning At this point the authors conclude that there is a link between environmental exposure to mercury and autism

While this may seem like an appropriate test to most people there are several problems with the approach taken here:

  • The actual levels recorded of these two chemicals are not reported, only the overall ratio
  • Measurements of one of the chemicals (creatinine) are known to be prone to inaccuracies, which means the ratios measured are not useful
  • The actual levels of mercury, or any other heavy metal, were not measured So they are only being guessed at by an indicator which is inaccurate in this application
  • The research references some highly questionable research, such as the infamous baby hair research
  • It is worth noting that the senior author has a "peculiar relationship" with a leading anti-vax individual

Ultimately, at BEST this can be evidence that autism is influenced by environmental exposure to heavy metals, although even that conclusion is difficult to draw given the evidence presented Even given this generous interpretation, it does nothing to suggest the levels or method of exposure found in vaccines could have any effect

You can read more about this evidence here:



Strength/Weakness 1

Mild weakness: Industry Independence
The lead author appears to have known ties to anti-vax people

Strength/Weakness 2

The research does not appear to have any industry funding.

Strength/Weakness 3

Strong weakness: Well Designed Research

The research relies upon bad science, ignoring known inconsistancies in certain readings in autistic individuals. Even ignoring those weaknesses this research would introduce an avenue of research at best without actually demonstrating heavy metals cause autism.

Conclusion 1

It is claimed by many that this research provides evidence that vaccines cause autism Even being generous with the methodology, at best this research shows a that environmental exposure to heavy metals may play a part in autism That is a far cry from demonstrating that the very small levels of thimerosal found in some vaccines is linked to autism

Conclusion 2

If we ignore the flaws in the research methodology it could be said this research warrants further investigation into a link between heavy metal exposure and autism.

Bad text to replace:
Correct text:
Close This is a proper word Ignore word on this page Apply
Close Popup
Follow Reasoned Discussions on Facebook
Share this page on Facebook
Follow Reasoned Discussion on Google+
+1 this page on Google+
Terms of Use | Site Map | Privacy