Autism Spectrum Disorder (ASD) is a developmental disability characterized by variations in brain structure and function. While some individuals with ASD have identifiable genetic conditions, the underlying causes for many remain elusive. Scientists hypothesize that ASD arises from a combination of factors, both genetic and environmental, which collectively alter typical developmental pathways. [1] Prenatal toxins are one of many factors that affect ASD. Infants born to mothers with Pre-Gestational Diabetes Mellitus (PGDM) or Gestational Diabetes Mellitus (GDM) may experience mild developmental challenges post-birth. These difficulties can impact both fine and gross motor skills, potentially increasing the likelihood of learning difficulties and attention deficit hyperactivity disorder (ADHD), a common neurological issue in autism spectrum disorder (ASD). The adverse effects of maternal diabetes on fetal brain development may stem from heightened intrauterine oxidative stress, epigenetic alterations in gene expression, and other yet unknown factors. Although maintaining good diabetes control during pregnancy can mitigate these risks, it may not eliminate them. Research indicates a correlation between maternal rubella infection and a heightened incidence of ASD, whereas infections such as Toxoplasma, Parvovirus, and Tic bone do not appear to be associated. These changes may contribute to the development of conditions like autism spectrum disorder (ASD) as the child grows. [2] Inflammation is another factor that links or contributes to ASD, inflammation affects the immune system and certain proteins called cytokines, which play a role in the body’s response to infection. Scientists are studying how this inflammation affects the brain using both animal models and lab experiments. They want to understand how these immune responses impact the development of autism. When a pregnant woman gets sick, her body releases certain chemicals. These chemicals activate special immune cells in her body, which then release more chemicals. These immune responses not only affect the mother but also reach the placenta, a special organ in the womb. The placenta has its immune cells, and when it detects these chemicals, it starts making more of them. This can cause harm to the placenta and let these inflammatory chemicals enter the baby’s developing body. The baby then starts making similar chemicals. Eventually, these harmful chemicals can reach the baby’s brain and cause swelling and other problems. [3] Environmental Factors such as exposure to metals, pesticides, and other contaminants can also contribute to the possibility of the child having autism. Researchers found that the high consumption of fish, especially for those living in the Republic of Seychelles because the fish contain mercury, exposures for those living in the Republic of Seychelles this is because the fish contain mercury, exposures to other metals such as lead, arsenic, zinc, or manganese are also in this category. [4] Various theories effectively explain the understanding of Autism. The E/I imbalance theory suggests that a decrease in GABAergic neurons can lead to seizures. In the brain’s striatum, medium spiny neurons (MSNs) receive signals from the thalamus and dopamine-producing neurons from the substantia nigra. These MSNs become active just before initiating movements. Changing how dopamine affects these MSNs could upset the E/I balance in the striatum, potentially causing symptoms of ASD. This is significant because the striatum is crucial for choosing actions and behaviors related to rewards. The altered network connectivity theory suggests that there’s a problem with how brain cells communicate. More severe symptoms of ASD are linked to larger distortions in how brain areas connect between the two hemispheres. The predictive coding hypothesis proposes that our brains predict what we expect from the world around us and adjust when things don’t match up. This might relate to why individuals with ASD prefer routines and repetitive behaviors—they may have different expectations about their environment.
https://doi.org/10.3390/ijms222111516
[1] “What Is Autism Spectrum Disorder?” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 9 Dec. 2022, www.cdc.gov/ncbddd/autism/facts.html.
[2] Ornoy, A., et al. “Prenatal Factors Associated with Autism Spectrum Disorder (ASD).” Reproductive Psychology, Prenatal factors associated with autism spectrum disorder (ASD), 26 May 2015, www.sciencedirect.com/science/article/abs/pii/S0890623815000751?via%3Dihub.
[3] Zawadzka A, Cieślik M, Adamczyk A. The Role of Maternal Immune Activation in the Pathogenesis of Autism: A Review of the Evidence, Proposed Mechanisms and Implications for Treatment. International Journal of Molecular Sciences. 2021; 22(21):11516.
[4] “Autism.” National Institute of Environmental Health Sciences, U.S. Department of Health and Human Services, 19 Apr. 2023, www.niehs.nih.gov/health/topics/conditions/autism#:~:text=Air%20pollution%20%E2%80%93%20Researchers%20found%20early,as%20likely%20to%20develop%20ASD.
