By Rideeta Raquib

Autism spectrum disorder (ASD) refers to a classification of developmental disabilities characterized by changes in social communication, as well as repetitive and restricted patterns of behavior or interests. Approximately 50 percent of ASD risk is linked to genetics and the rest is attributed to environmental factors, including fetal or early childhood exposure to toxic metals and nutrient deficiencies. Researchers from The Senator Frank R. Lautenberg Environmental Health Sciences Laboratory and The Seaver Autism Center for Research and Treatment at Mount Sinai developed tooth-matrix biomarkers that are capable of measuring fetal and postnatal exposure to various metals. Twins from population-based cohorts were recruited and naturally shed teeth were collected.

The teeth samples were examined with the tooth-matrix biomarkers. The fetal biomarkers provide time-series data from the second trimester onwards on multiple metal exposures. The researchers hypothesized  that prenatal and early exposure to metal toxins or deficiency of essential elements during critical development are associated with ASD. Lead and manganese were some of the key focuses of the study, because of their neurotoxicity and association with behavioral outcomes of ASD. Zinc was also an element of focus due to its role in health maintenance and metal transport.  The study concluded that  higher amounts of lead were observed over the prenatal period and 5 months postnatally in ASD patients. Important elements were also observed to diminish at certain developmental phases. Zinc was lowest during the third trimester and manganese was lowest 4 months post birth.

Overall the hypothesis of the study was supported, in that whether it be an excess or deficiency of various metals during specific developmental intervals correlate with ASD. This finding will open up a path for more research regarding ASD taking environmental factors into account instead of just genetic factors.

References:

1. Manish Arora, Abraham Reichenberg, Charlotte Willfors, Christine Austin, et al. Fetal and postnatal metal dysregulation in autism. Nature Communications, 2017; 8: 15493 DOI: 10.1038/NCOMMS15493
2. Image acquired from: https://sbyireview.files.wordpress.com/2017/06/7fde6-1492806086476.jpg