Autism Causes
AUTISM CAUSES
Although a large amount of research has gone into autism, its causes are still not absolutely clear. Autism may be the result of an abnormality with the neurologic functions but the exact cause is unknown, in most cases.Some research findings point to a large genetic component but most researchers believe that environmental, immunologic, and metabolic factors also play a role in the development of autism.
Autism Causes
No single gene or genetic defect has been identified that can be implicated as the cause of autism. Causes of autism have been thought to include a number of genes that, combined, increase the risk of autism. Researchers suspect that there are a number of different genes that, when combined together, increase the risk of getting autism. A number of research studies indicate that first-degree relative of people with autism have a greater risk of autism.
Clinical experience of autism, its causes and autism spectrum disease reveals that sometimes an underlying condition may be responsible for autism.For example, some metabolic disorders like untreated phenylketonuria, congenital infections like rubella and toxoplasmosis and disorders like tuberous sclerosis may lead to autism. Some other autism causes have been identified to be developmental brain abnormalities like microcephaly, macrocephaly and cerebral dysgenesis as well as neurologic disorders acquired after birth like lead encephalopathy and bacterial meningitis. But is is also true that these medical disorders are not the sole autism cause.
At one time it was believed that one important autism cause was bad parenting but this theory has been resoundingly debunked. Another theory,which has refused to die down is the mercury content of some preservatives used in medical vaccines.
A large majority of people who suffer from autism have a slightly enlarged brain size[1]. This enlargement of the brain of people with autism is a well-known fact but the exact relationshipis unknown.
In a book written by Professor Simon Baron-Cohen of the Autism Research Center, the professor has argued for a very unusual autism cause - namely that autism is a manifestation of an extreme form of the differences in the male and the female brains[2][3].However, the concept of different types of intelligence in males and females is unsubstantiated and speculative.
The cells of the limbic system (responsible for regulating emotion and complex learning) in an autistic person are smaller and more densely packed than that of a normal brain. This is seen quite often in autism and causes inability to control their emotions as well as how they gain knowledge through repetition instead of analysis.
References
1. Samson, K. (2002). New studies shed light on brain changes in early autism. Neurology Today. 2(8),18-19.
2. Baron-Cohen S, Knickmeyer RC, Belmonte MK (2005). "Sex differences in the brain: implications for explaining autism". Science 310 (5749): 819b??23. PMID 16272115
3. Baron-Cohen S (2002). "The extreme male brain theory of autism". Trends in cognitive sciences 6 (6): 248b??254. PMID 12039606