Post by Amtram on Jun 19, 2014 10:54:36 GMT -5
SFARI, an organization that is dedicated to autism research, has an article entitled, What constitutes 'environmental' risk for autism? It consists of comments from scientists working in the fields of genetics, epigenetics, and pediatrics/autism in response to an article they published previously on a study done in Sweden. It's been presented as evidence that autism is caused almost equally by genes and environment, although previous studies (notably, twin studies) indicated that the heritability was closer to 90%.
Each contributor points to a different area to consider. There are complex factors in the heritability of autism, and some of them were not considered in the study. There is also the danger of misinterpretation - this is a pet peeve of mine when findings are made public and journalists conflate the findings with speculation. Kevin Mitchell, Associate Professor of Genetics at Trinity College in Dublin and author of Wiring the Brain points out:
Because people are so quick to jump on the environmental causation bandwagon, this is of great concern. We still have a vocal contingent of people who believe that vaccines cause autism (they don't.) Every conversation about ADHD ends up with people blaming cigarettes or lead or (believe it or not) GMOs. Nobody wants to consider that their children were born with a brain difference that was caused simply by a set of genes that built it - it needs to be the "fault" of something outside of themselves. We're perfectly fine with the idea that we inherited genes for heart disease or breast cancer or height, hair color, vision impairment - pretty much anything except for the brain.
When you look at it, the brain is just another organ, like any other in the body. It's built the same way, with genetic instructions that are set in motion the moment sperm and egg combine. If you're going to blame an environmental factor, you need to name it, study it, and establish a strong correlation before you infer causation. Research that gives laypersons the opportunity to "choose their own adventure" does nothing to further the cause of actually studying the diagnosis and treatment of brain disorders.
Each contributor points to a different area to consider. There are complex factors in the heritability of autism, and some of them were not considered in the study. There is also the danger of misinterpretation - this is a pet peeve of mine when findings are made public and journalists conflate the findings with speculation. Kevin Mitchell, Associate Professor of Genetics at Trinity College in Dublin and author of Wiring the Brain points out:
The conclusions of an important effect for the environment should be tempered, especially given how they can be misinterpreted and misrepresented. The fact that monozygotic twins are not always concordant for the disorder suggests there are some non-genetic factors that contribute to whether individuals develop the disorder or not. In the analytical models used here, these sources of variance are bundled into a statistical term called the ‘non-shared environment.’ This term is used here in a technical sense that does not correspond to the colloquial meaning. In particular, it should not be taken as evidence of effects of some causal factors out in the environment.
Because people are so quick to jump on the environmental causation bandwagon, this is of great concern. We still have a vocal contingent of people who believe that vaccines cause autism (they don't.) Every conversation about ADHD ends up with people blaming cigarettes or lead or (believe it or not) GMOs. Nobody wants to consider that their children were born with a brain difference that was caused simply by a set of genes that built it - it needs to be the "fault" of something outside of themselves. We're perfectly fine with the idea that we inherited genes for heart disease or breast cancer or height, hair color, vision impairment - pretty much anything except for the brain.
When you look at it, the brain is just another organ, like any other in the body. It's built the same way, with genetic instructions that are set in motion the moment sperm and egg combine. If you're going to blame an environmental factor, you need to name it, study it, and establish a strong correlation before you infer causation. Research that gives laypersons the opportunity to "choose their own adventure" does nothing to further the cause of actually studying the diagnosis and treatment of brain disorders.