Causes of Autism

Genetic
Abnormalities in brain structure
Biochemical disorders
Viral Infection
Yeast/Candida infections
Allergies and food sensitivities (milk and wheat products)
Dysfunctional immune system.

The Genetic Component

A study done at the University of Washington suggested there might be six or more genes that have to come together in one individual in the right form to lead to autism. Researchers have identified only one specific genetic connection with autism - fragile X syndrome, which is also the most common cause of genetically inherited mental retardation. According to the National Fragile X Foundation of USA, between 2 and 6 percent of all children diagnosed with autism have a fragile X gene mutation, and approximately one-third of all children with fragile X have autism. If a child with autism also has fragile X, there is one-in-two chance that boys born to the same parents will have fragile X syndrome. If one identical twin has autism, there is a 90 percent chance that the other will have autism as well. Research done at Yale Child Study Centre has shown that if you have given birth to a child with autism, there is one-in-twenty chance of giving birth to another child with autism (Exkorn, Karen Siff. The Autism Sourcebook. New York: Harper Collins Publishers Inc., 2006 (p.73)).

The Brain Component - The Underconnectivity Theory

There is a disruption of circuitry in brains of children with autism. Some parts are over-connected; some are under-connected. There are early developmental cues that point to brain abnormalities; smaller head size at birth followed by a period of excessive head growth between 6 months and 2 years of age, where chronic inflammation occurs in the areas of excessive growth. In the frontal lobes where nerve cells are responsible for higher order processing like decision-making and social reasoning, the nerve cells are much smaller than normal.

The Environmental Component

Possible environmental factors include viral infections, exposure to environmental chemicals such as lead and mercury, environmental toxins such as PCBs (polychlorinated biphenyls), and metabolic imbalances.

The Immune System Component

Children with autism seem to have lower levels of cytokines, which are protein molecules that help mediate the body's immune reponse and influence both behaviour and mood.

The Immunization Component

Queries had been raised concerning MMR (Mumps, Measles, Rubella) vaccine and vaccines that contain thimerosol, a mercury preservative found in immunizations for hepatitis, whooping cough, tetanus, and diphtheria. However, to date, no scientific study has discovered beyond a doubt that a link exists between immunization and autism.