The purpose of this review is to examine the parallels between the effects
mercury intoxication on the brain and the brain pathology found in
autism spectrum disorder (ASD). This review finds evidence of many parallels between the two, including: (1) microtubule degeneration, specifically large, long-range axon degeneration with subsequent abortive axonal sprouting (short, thin axons); (2) dentritic overgrowth; (3)
neuroinflammation; (4) microglial/astrocytic activation; (5) brain immune response activation; (6) elevated
glial fibrillary acidic protein; (7) oxidative stress and lipid peroxidation; (8) decreased
reduced glutathione levels and elevated
oxidized glutathione; (9)
mitochondrial dysfunction; (10) disruption in
calcium homeostasis and signaling; (11) inhibition of
glutamic acid decarboxylase (GAD) activity; (12) disruption of GABAergic and glutamatergic homeostasis; (13) inhibition of
IGF-1 and
methionine synthase activity; (14) impairment in methylation; (15) vascular endothelial cell dysfunction and pathological changes of the blood vessels; (16) decreased cerebral/cerebellar blood flow; (17) increased
amyloid precursor
protein; (18) loss of granule and Purkinje neurons in the cerebellum; (19) increased pro-inflammatory
cytokine levels in the brain (TNF-α, IFN-γ, IL-1β, IL-8); and (20) aberrant nuclear factor kappa-light-chain-enhancer of activated B cells (
NF-kappaB). This review also discusses the ability of
mercury to potentiate and work synergistically with other toxins and pathogens in a way that may contribute to the brain pathology in ASD. The evidence suggests that
mercury may be either causal or contributory in the brain pathology in ASD, possibly working synergistically with other toxic compounds or pathogens to produce the brain pathology observed in those diagnosed with an ASD.