The vaccine theory is dead. What’s left?
In January, after many years of inaction, British medical regulatory officials finally found Dr. Andrew Wakefield guilty of unethical behaviour in carrying out research that, he claimed, showed a connection between the measles-mumps-rubella (MMR) vaccine and autism. Soon after, The Lancet issued a full retraction of Dr. Wakefield’s 1998 paper, turning the page on an ugly chapter in the journal’s recent history that saw most of the coauthors disavow the
autism/vaccine theory. That theory, already shown to be unsupported by the evidence in large studies, truly no longer holds water. So what actually causes autism?
We asked Jeanette Holden, PhD (left), program director of the Autism Spectrum Disorders - Canadian-American Research Consortium (ASD-CARC), to describe the latest science on autism’s etiology. Dr. Holden, who studied genetics with David Suzuki, is also a professor of psychiatry and physiology at Queen’s University and sits on the board of Autism Society Canada.
INTERVIEW
PE We know it’s not vaccines, so what are the current ideas about what causes autism?
JH It’s quite clear there are two components to all complex disorders -- diabetes, asthma, and so on. Autism is no different. Both genetics and the environment play a role. We know genetics is critical because when you look at a number of patients you often see something very similar to autism, or at least that has some of the components of it. We call that the broader phenotype . That is, there may be some of the social problems and some of that rigidity, almost that one-track mind, the ability to concentrate on something. We see that often in families. Hyperactivity is common in families with autism. Quite often there’s depression in the family. When you start to see a clustering of underlying similar conditions, you really do have to think that genes are somehow involved here. There have been a lot of discoveries in the last few years of specific chromosome changes that happen. It’s not the same change in everybody, but a lot of different changes: small deletions and duplications, or copy-number variants. So there is definitely this genetic component, but we don’t know about factors within the environment -- chemicals or something in our diet -- that might also be contributing to this, and that is going to take a long time to sort out.
Click here to read the rest of this article on the Parkhurst Exchange website.
Photo: ASD-CARC
Friday, 12 March, 2010
What really causes autism?
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