There is, nevertheless, a significant relationship between mercury concentration and autism. Thus, the concentration for mercury can be listed as a pathogenic cause (disease-causing) for autism.
Jafari Mohammadabadi H, Rahmatian A, Sayehmiri F, Rafiei M. The Relationship Between the Level of Copper, Lead, Mercury and Autism Disorders: A Meta-Analysis. Pediatric Health Med Ther. 2020;11:369-378 https://doi.org/10.2147/PHMT.S210042
In this study, 18 articles conducted in different countries from 1982 to 2019 were collected to determine the authenticity or lack of relationship between the concentrations of copper, lead, and mercury and autism and to provide a reliable pattern in the field for the researchers and planners. Results: In these 18 studies, 1797 patients (981 cases and 816 controls) aged 2 to 16 years were examined. Concentration of the samples (blood, hair, and nails) for both case and control groups was evaluated. There was no significant relationship between copper concentration and autism; there was a significant relationship between mercury concentration and autism; there was also a significant relationship between lead concentration and autism.