Higher rates of autism diagnosis in recent years suggest involvement of environmental factors in causing this developmental disorder, notwithstanding genetic risk factors. Autistic children exhibit evidence of oxidative stress and impaired methylation, which may reflect effects of toxic exposure on sulfur metabolism.
Note : the above is largely inspired by Deth R, Muratore C, Benzecry J, Power-Charnitsky VA, Waly M: How environmental and genetic factors combine to cause autism: a redox/methylation hypothesis. Neurotoxicology. 2008, 29: 190-201. 10.1016/j.neuro.2007.09.010.
There are probably many environmental factors and they can potentially be combined. Following a workshop entitled « Exploring the Environmental Causes of Autism and Learning Disabilities » and organised with the support of the National Institute of Environmental Health Sciences (NIEHS) and the Autism Speaks association, the Mount Sinai Children’s Environmental Health Center compiled as early as 2011 a list of 10 chemical compounds suspected of neurodevelopmental toxicity:
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Lead (Jusko et al. 2008)
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Methylmercury (Oken et al. 2008)
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Polychlorinated biphenyls (Winneke 2011)
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Organochlorine pesticides (Eskenazi et al. 2007; London et al. 2012)
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Organochlorine pesticides (Eskenazi et al. 2008)
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Endocrine disruptors (Braun et al. 2011; Miodovnik et al. 2011)
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Automotive exhaust (Volk et al. 2011)
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Polycyclic aromatic hydrocarbons (Perera et al. 2009)
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Brominated flame retardants (Herbstman et al. 2010)
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Perfluorinated compounds (Stein and Savitz 2011).
For families
Toxicological risks are not always identifiable in the history of an autistic person. Treatment approaches are still in the research phase but are advancing rapidly.
This list was not complete and will almost certainly expand in the years ahead as new science emerges. It was intended to focus research in environmental causation of neurodevelopmental disabilities on a short list of chemicals where focused studies have high potential to generate actionable findings.
Note : the above comments are largely inspired from : Landrigan PJ, Lambertini L, Birnbaum LS: A research strategy to discover the environmental causes of autism and neurodevelopmental disabilities. Environ Health Perspect. 2012, 120: 258-260. 10.1289/ehp.1104285.
Furthermore, the comprehensive cohort review carried out in 2024 by Ahrens et al. underscores meaningful links between early-life infections and neurodevelopmental disorders. These correlations expand the list of potential triggers to include immunological events.
Reference : Ahrens et al., Infant microbes and metabolites point to childhood neurodevelopmental disorders, 2024, Cell 187, 1853–1873 April 11, 2024 Published by Elsevier
