rebuttal to whelans silly article Great Unfounded Health Scares of 2004

[Guest guest]

Wait for the Autism Fat Lady to Sing

By C. Deth Published 12/30/2004

Dr. Whelan bravely puts the autism-thimerosal connection at the

top of her list of " Great Unfounded Health Scares of 2004 " . While we all

might like this dark side of vaccines to be just a crackpot idea, recent

studies have provided solid evidence indicating that toxic effects of the

ethylmercury-containing preservative may indeed have led to recent increases

in autism and ADHD.

Since 1985, the incidence of autism has risen from 1 in 10,000 to about 1 in

150, and ADHD affects about 8% of kids. This rise parallels increased

ethylmercury exposure from vaccines, at least through 2001, raising the

question: Could they be related? Several epidemiological studies, quickly

embraced by an investigating panel from the Institutes of Medicine, did not

find evidence of a link. However, internal FDA memos clearly indicate that

original data supporting a link was massaged and revised until the link

disappeared, at which time the data was deemed suitable for publication.

Moreover, investigating disorders of relatively low frequency with

epidemiological methods has severe statistical limitations. How about

studies of autistic children? Are autistic kids somehow different in a way

that makes them thimerosal-sensitive? The emerging answer seems to be yes.

A recently published study in the American Journal of Clinical Nutrition by

Dr. Jill and colleagues found abnormal plasma levels of metabolites

related to methylation, a biological process involving transfer of single

carbon atoms between molecules. Treating these kids with a form of folic

acid, along with a source of methyl groups and the active form of vitamin

B12, known as methylB12, caused their metabolite levels to normalize and

also improved their autism symptoms. Thus autism can be recognized as a

metabolic disorder affecting the capacity for methylation.

As it turns out, thimerosal is a potent inhibitor of the same methylation

pathways that are involved in autism. In April 2004, an article in Molecular

Psychiatry described how thimerosal, along with other well-accepted

neurodevelopmental toxins (e.g. lead, mercury and alcohol), blocked folic

acid-dependent methylation in human neuronal cells. DNA and gene expression

were also affected by methylation, providing a link to impaired development.

Subsequent studies revealed that thimerosal inhibits methylation by blocking

conversion of dietary or vitamin-derived forms of vitamin B12 to methylB12.

Thus the beneficial effects of methylB12 in autism reflect its ability to

bypass the toxic action of thimerosal.

Autism is highly genetic, meaning that inherited genes provide a major

source of risk. Many of the genes controlling folic acid-dependent

methylation exhibit variations called polymorphisms. While usually harmless,

these polymorphisms can combine to increase risk, and can interact with

environmental factors. Analysis of DNA from autistic children has shown a

higher frequency of these polymorphisms, indicating that they are indeed a

genetically distinctive sub-population that is at risk for environmental

insults directed toward methylation.

ADHD is closely related to autism and over 75 studies have been published

linking it to a particular receptor for the neurotransmitter dopamine,

called the D4 receptor. This D4 receptor has the unique ability to carry out

a methylation reaction, which is potently inhibited by thimerosal. The D4

receptor is highly developed in humans and primates, suggesting a critical

role in our capacity for attention-related learning. It is no wonder that

the deficits in autism (e.g. lack of language, impaired social skills)

reflect a loss of some of the most uniquely human traits and abilities.

As humans we use attention to direct our thoughts for the purpose of solving

problems and to advance our personal well-being and the well-being of our

social structures. Technology is an important manifestation of this

capability. We cannot afford to take these capabilities for granted.

Exposure to neurodevelopmental toxins, whether in the form of vaccine

preservatives (e.g. flu vaccine), mercury-tainted tuna fish during pregnancy

or lead paint, can rob a portion of our population of their capabilities.

The lesson of thimerosal and autism is a cautionary tale that must be

understood. Could there be other disorders whose increase might be related

to heavy metal exposure? Perhaps this is a question for technology to

address.

Wait! I think I hear someone singing.

The author is Professor of Pharmacology, Northeastern University.

Copyright © 2004 Tech Central Station - www.techcentralstation.com