View Full Version : Genes Are NOT the Main Cause of Autism

11th August 2012, 05:38 PM
Many scientists have believed that genetics accounted for 90 percent of a child's risk for autism. A new study, however, suggests that environmental factors could play a much larger role.

The research looked at nearly 200 pairs of twins, and found, to the researchers’ surprise, that a greater number of fraternal twins shared autism than identical twins. Fraternal twins share only half their genes with each other.

According to NPR:

"Scientists have long suspected that there's been an environmental contribution to autism ... and previous studies have shown that it may occur in the early stages of pregnancy."

For a truly eye-opening look at the causes of autism, watch this interview with Dr. Natasha Campbell-McBride -- a physician who cured her own son of the disorder.

Dr. Mercola's Comments:

Autism was a very uncommon condition when I was in medical school; it impacted maybe one in 10,000 children. Now we are seeing an explosion of cases numbering somewhere between 1 in 50 and 1 in 110 children, depending on what source of statistics you use.

Clearly something is going on, but it is most likely not a problem with genetics in the majority of cases, as conventional medicine has often suggested. Research is now clearly showing that environmental factors play an equal, if not more important, role in the epidemic of autism spectrum diseases.

Environmental Factors Play a Major Role in Autism

The latest research from Stanford University School of Medicine used identical twins to help unravel a part of the puzzle. Since identical twins share nearly the same DNA, if there were an important genetic component to autism, then if one identical twin has autism, so should their identical sibling in the vast majority of cases.

However, when researchers completed diagnostic assessments on 192 twin pairs, they found fraternal twins were more likely to share an autism diagnosis than identical twins. Fraternal twins share only 50 percent of their DNA, which means something else is probably responsible for the double diagnosis -- and researchers suspect environmental factors are likely to blame. They note:

"Susceptibility to ASD [autism spectrum disorder] has moderate genetic heritability and a substantial shared twin environmental component."

This is not an entirely surprising finding, as even though researchers did find a genetic mutation linked to autism in a study conducted in 2008, the mutations are present in only 1 percent of all kids with autism. Furthermore, no one has been able to identify one single "autism gene." And there is no such thing as a genetic epidemic -- so no way to explain today's autism explosion as a function of genetics. The majority of autism cases appear to result from the activation, or "expression," of a number of different genes and multiple epigenetic and environmental factors that interact to express autism traits.

Is Your Gut Flora the Most Important Common Thread?

When looking into the possible environmental factors for autism, they are incredibly diverse. For instance, a recent review by Helen Ratajczak in the Journal of Immunotoxicology found autism may be the result of inflammation of the brain due to:

Encephalitis following vaccination Defective placenta Immature blood-brain barrier
Immune response of the mother to infection while pregnant Premature birth Encephalitis in the child after birth
Toxic environment
Russian neurologist Dr. Natasha Campbell-McBride recently shared a common thread that may be linking these and other environmental factors together – brain toxicity that stems from gut toxicity, otherwise known as Gut and Psychology Syndrome

source - Dr Mercola