Two new studies by international teams, including Egyptian scientists, have validated the link between autism and mercury.
In an article published in the journal Metabolic Brain Disease, a team of nine scientists from leading Egyptian universities and medical schools confirmed the causal role of mercury in the onset of autism.
At least six American studies have linked autism presence or severity to mercury exposure as determined by measuring urinary porphyrins.
The scientists determined the extent of mercury poisoning in children by measuring urinary excretion of organic compounds called porphyrins, which act as biomarkers for mercury toxicity. The researchers also measured blood levels of mercury and lead. The researchers found a strong relationship between mercury toxicity and the presence of autism and a direct correlation between levels of mercury toxicity and the severity of autism symptoms.
The scientists studied 100 children; 40 with autism spectrum disorder (ASD), 40 healthy individuals and 20 healthy siblings of ASD children. The results showed that the children with ASD had significantly higher mercury levels than healthy children and healthy siblings. Children with the highest mercury levels had the most severe autism symptoms.
At least six American studies have linked autism presence or severity to mercury exposure as determined by measuring urinary porphyrins. The first study, completed by Heyer et al. in 2012 (Autism Res 5:84) showed a correlation between the presence of autism and specific urinary porphyrins associated with mercury toxicity. This affirmed an earlier study by Kern et al. (2011, Pediatr Int 53:147) where specific porphyrins associated with mercury toxicity were significantly higher in ASD children as compared to non-autistic controls. Woods et al. (2010, Environ Health Perspect 118:1450) also saw disordered porphyrin metabolism in autistic kids which was not observed in non-autistic control children. This again suggested increased mercury toxicity associated with autism and autism spectrum disorder.
Autism severity has also been correlated to levels of specific porphyrins associated with mercury toxicity. Kern et al. in 2010 (Biometals 23:1043) showed a strong relationship between the level of autism severity as measured by the Autism Treatment Evaluation Checklist (ATEC) instrument and the amount of urinary porphyrins observed in ASD children. Geier et al. (2009, J Toxicol Environ Health A 72:1585) also correlated urinary porphyrins to autism severity in a blind study using the childhood autism rating scale (CARS). This study was further elucidated by Geier et al. (2009, J Neurol Sci 15:280) where children with severe autism showed significantly higher urinary porphyrins associated with mercury toxicity as compared to those children with mild autism and non-autistic controls. Other biomarkers measured in this study correlating mercury toxicity with autism severity include the presence of glutathione, cysteine and sulfate metabolites in plasma.
In a second study, by Mostafa et al., published in Metabolic Brain Disease in June 2016, an international team of Egyptian, Norwegian, Saudi Arabian and Chilean physicians and scientists used a different set of measurement protocols to find a direct correlation between mercury levels and autism diagnosis. The reasearchers measured levels of neurokinin A and B - pro-inflammatory neuro peptides that indicate the presence of mercury in the blood – in 84 children with ASD and 84 controls. The results showed a positive linear relationship between mercury levels and the severity of autism symptoms.
Many of the mothers of children in the first 2016 Egyptian study (Khaled et al.) had multiple dental amalgams which may have contributed to the children's body levels of mercury. The study does not examine the potential link between autism and the vaccine preservative, thimerosal, which is 50 percent ethyl mercury by weight. However, other studies indicate that the ethyl mercury in thimerosal is 50 times as toxic to human tissue as the methylmercury in amalgams and fish (Guzzi et al. 2012, Interdiscipl Toxicol 5:159) and at least twice as persistent in the brain (Burbacher et al. 2005, Environ Health Perspect 113:1015).
The 2016 Metabolic Brain Disease studies are only the latest in a series of important studies by leading Egyptian doctors and scientists linking mercury exposure to autism. A September 2015 paper published in Behavioral Neurology (Mohamed et al. 2015, PMID 26508811) by a group of researchers from the faculty of Cairo's Ain Shams University and the National Institute of Standards studied 100 autistic children and 100 healthy children. The researchers found significantly high levels of mercury, lead and aluminum in the autistic children (probably from maternal fish consumptions, living near gas stations and usage of aluminum paints) and concluded that "environmental exposure to these toxic metals at key times in development may play a causal role in autism."
A November 2014 study published in Environmental Toxicology and Pharmacology (38:1016) by Heba Yassa of the Assuit University Medical School's Department of Forensic Medicine and Clinical Toxicology, looked at 45 children with autism and 45 controls. Using blood and hair samples, Dr. Yassa also found high levels of lead and mercury among the children with autism and not the controls. Using dimercaptosuccinic acid or DMSA as a chelating agent, Dr. Yassa was able to reduce blood mercury and lead levels in the autistic children. His study documents significant declines in autism symptoms with the decrease of metals in the children's blood. The study's concluded: "Lead and mercury are considered as one of the main causes of autism. Environmental exposure as well as genetic inability of certain individuals to excrete metals is responsible for the high levels of heavy metals. Detoxification by chelating agents had a great role in improving those kids."
Dr. Yassa's study duplicated the results of numerous previous peer-reviewed papers and case studies. For example, Blaucok-Busch et al. 2012 Maedica 7:214 and Adams et al. 2009 BMC Clinical Pharmacol 9:17 documents improvements in autism symptoms and even loss of the autism diagnosis following mercury chelation.
Dr. Yassa's 2014 study supported earlier findings by a team of German and Egyptian government and university medical school scientists, which reported in a 2012 study published in Maedica, a Journal of Clinical Medicine (Blaucok-Busch et al. 7:214). The scientists studied the efficacy of DMSA chelation therapy in a sample of Arab children with autism spectrum disorder. That study found that oral DMSA chelation in 44 children with autism ages 3 to 9 reduced body burden of three metals—cadmium, mercury and lead—and that detoxification reduced their behavioral effects and neurological symptoms of autism.
These 2014 and 2012 Egyptian studies supported the findings of several other publications and case studies, suggesting that heavy metal chelation has a measurable therapeutic effect on autism. Other studies have reported significant improvement in the symptoms of autistic children following treatment with chelating drugs that remove metals from the body. In a 2002 study, 10 patients with autism were treated with a chelating agent. All but two of the patients showed improvement in their ATEC scores (Lonsdale et al., Neuro Endocrinol Lett 2002, 23:303). A study in 2003 by Jeff Bradstreet compared mercury excretion after three day treatment using the chelating agent, DMSA, and found that children with autism excreted three times the amount of mercury in their urine as the non-autistic control group (Bradstreet, et al., J Am Phys Surg 2003, 8:76).
These are only a sampling of the groundbreaking studies by Egyptian scientists, doctors and researchers on the etiology of autism. Impressive Egyptian studies beg a host of questions for public health officials and American citizens. Most prominently: why can a chaotic society in a war torn and relatively impoverished nation produce high quality science on the etiology and successful treatments of autism while the science on the environmental triggers of autism in the U.S. is stagnant despite the National Institutes of Health spending more than $1 billion on autism research since 2010?