P = G x E

The WSJ had an article the other day about an economist who is trying to figure out keys to autism. The economist is trying to correlate an increase in autism with an increased incidence of rain/snow. His hypothesis: the weather and autism are linked through the fact that children watch more TV when the weather is crappy outside and TV is a strong environmental component leading to autism. This economist adapted economic analyses to prove his point - and his methods are unorthodox.

Ok - I thought it was an interesting article.

As with anything like this, you get an interesting response.

The most interesting comes from Alison Singer, parent of a autistic child and senior VP of Autism Speaks. She states, "This is junk science. Autism is a genetic disorder. The only thing that the parents do wrong is they have bad genes."

Now I found it interesting that Autism Speaks is a non-profit founded by NBC Universal Chief Executive Bob Wright. Anyone see a conflict about a VP of a non-profit, using a non-profit funded by a television executive, discussing autism in absolute terms? Didn't happen to see a PhD after her name BTW.

Clearly Ms. Singer needs a little lession in genetics and Dr. Fag is here to lecture:

Central tenet to genetic analysis: genetics does not occur in a vacuum. The environment nearly always plays some role in genetics, and the observable result is what is called the phenotype.

Effectively, the interaction of your genes (i.e. your genotype or G) and the environment (E) collectively create a phenotype (P).

This interaction is written as: P = G x E

Now there are some traits where the number of genes are small and have a very clear effect (the environmental effect may have a small, or narrow, effect). Two examples: blood type and eye color. These are termed qualitative traits.

There are number of other traits that are alot more messy; the effects of genetics and environment are hard to delineate absolutely.

Take height as an example. You could have the genetic potential to be 6 feet tall, but you better have good nutrition, among a myriad of other environmental effects, to acheive that potential.

Another example might be weight - you may have a propensity to carry weight on a high carbohydrate diet, but in the absence of excess carbohydrates, you may not see that potential.

In these cases, extremes in the environment can mask the genotype. These genetic component of these sorts of traits (i.e. height, weight, etc) are generally the result of a number of genes working in concert with the environment and are termed quantitative traits.

Now I am not a human geneticist, but I can tell you that autism is not a qualitative trait. Autsim clearly has both environmental and genetic components and the interplay between the two is very complex - hence the spectrum of disorders that are grouped under autism and the range in severity among people with a common autistic disorder.

It is irresponsible of Ms. Singer to trivialize autism as purely bad genetic luck - her view is that autism is strictly genetic with no environmental component.

She tries to make autism like haemophila or phenylketonuria.

Most shocking to me, Ms. Singer fails to address the responsibility of the parents to ensure a balanced development for their children. Where is the data that autism has no enviromental component? Is there definitive evidence that TV plays no component in autism? Is TV good for a child's development?

*Crickets chirping*

Totally and completely irresponsible behavior on Ms. Singer's behalf. But then again, proceeds from TV pay her bills, so I guess she can't bite the hand that feeds?