Baby teeth from children with autism demonstrate more toxic lead and less essential elements than baby teeth from children without autism, according to a study published in Nature Communications.
This evidence, published by researchers from The Senator Frank R. Lautenberg Environmental Health Sciences Laboratory and The Seaver Autism Center for Research and Treatment at Mount Sinai in New York City, New York, builds on earlier research about the effects of toxic metal exposure on the brain. It suggests that systemic dysregulation of environmental pollutants and dietary elements may play an integral role in autism spectrum disorder (ASD).
Manish Arora, PhD, BDS, MPH, director of exposure biology at the Lautenberg Laboratory, and colleagues studied twins to control genetic influences and focus possible environmental causes of ASD. “Our primary focus was on lead, an established neurotoxicant that that has been implicated [to] in ASD, and manganese, an essential nutrient with emerging evidence of neurotoxicity,” Dr Ahora explained.
The researchers studied 32 twin pairs and 12 individuals from twin pairs whose siblings did not provide a tooth. Using lasers to map growth rings in baby teeth generated during distinct developmental periods, they observed significant differences between ASD cases and non-ASD controls: in the ASD cases, researchers observed higher levels of lead in the prenatal period and the first 5 months after birth.
Children with ASD had lower zinc levels earlier in the womb, but these levels were higher after birth compared with non-ASD controls. There were smaller differences in the patterns of metal uptake when both twins had ASD; larger differences were observable when only 1 sibling had ASD.
“Our study…highlights a need to study the kinetics of metal mixtures during fetal and early postnatal development as we noted substantial shifts in metal levels between the pre- and post-natal periods,” the researchers wrote.
“Using novel biomarkers of early life exposure, we observed differences in uptake of multiple toxic and essential elements over the second and third trimesters and early postnatal periods in monozygotic and dizygotic twins discordant for ASD,” they concluded. “Developmental windows for the observed discrepancies varied for each element, suggesting that systemic elemental dysregulation may serve an important role in ASD etiology.”
Arora M, Reichenberg A, Willfors C, et al. Fetal and postnatal metal dysregulation in autism [published online June 1, 2017]. Nat Commun.doi:10.1038/ncomms15493.