Environment Effects And Autism
| Autism can be defined as a developmental disorder of the brain characterized by abnormalities of social interactions, impaired ability to communicate, stereotypic behavior and restricted interests. First signs of autism appear during infancy or childhood. There are several factors associated with the cause of autism. These include chromosomal abnormalities during child birth, teratogens and other environmental factors.
Chromosomal abnormalities are caused due to mutations occurring in genes. Exposure of embryo to various kinds of teratogens such as thalidomide, valproic acid and misoprotol can also cause autism. However, the primary causative agents triggering abnormal neuronal development in children are different kinds of environmental pollutants like heavy metals such as mercury, cadmium, nickel and lead, PCBs, pthalates, pesticides, alcohol, smoking, brominated flame retardants, drugs and phenols.
Autism was a rare occurrence among children during 1980s when the environmental pollutant levels were low. The situation has become alarming. It is reported that 1 child in every 150 American children suffers from autism.
There is extensive data regarding the effects on environmental pollutants causing genetic abnormalities during child birth. Most of the genes participating in neuronal connectivity and synaptogenesis are mutated due to environmental toxicants resulting in an abnormal expression of proteins in the nervous system. Recently, researchers have also found that mercury present in air and water can also cause autism. Mercury is the most common pollutant released from power plants, dye industries, leather industries and those that are burning fossil fuels. There are incidences of autism caused by thimerosal, a preservative agent used in child vaccines.