28th of April 2009: Dr. Hakon Hakonarson, MD, PhD, director of genomics research at The Children's Hospital of Philadelphia is leading two research published in the journal Nature, along with two other studies uncovering more clues to autism -- one also published in Nature and the other in Annals of Human Genetics. Dr. Hakonarson suggests to have identified new and common gene mutations -- also called gene variants that raise the susceptibility to develop autism.
A region of chromosome 5 that involves genes that facilitate cell-to-cell communication -- CDH9 and CDH10 was named. Other genes claimed to be involved in brain development and cell-cell interaction in the nervous system were also suggested to be potential candidates. More report from the traditional view point here.
However there are serious limitations to the interpretation of these findings.
The mentioned genes have not been identified and proven to be related to autism in the studied subjects. A duplication, or single nucleotide polymorphism does not necessarily cause a phenotype. Futhermore, the genes mentioned makes sense within a paradigm of neurological brain development disorder but we should not forget that many of these genes, e.g. cadherins, CNTN4, ubiquitin actually also have function in regulating the immune system. If these mutations are genuinely related to autism, is that because they cause abnormalities of brain development or make the individual more susceptible to insult of an immune origin? This question can only be addressed in animal model, a “Knock In”, as we call it, which replaces a gene with a potentially “mutant” version of, it in the mouse genome.
Generally speaking though, even if a developmental gene, is involved in as little as 1% of the ASD population even with as little at 1% of the overall contribution, that would be an important finding. But the point is, should a study that identify plausible cause of a condition in only 1% of individuals and that requiring huge sums of money be conducted? Isn’t it a little bit like going to the moon? And what is that for? This is where one should look behind the scene, what are the true motivations behind these studies. Sorry to say, but it has, as often, little to do with science and health.
A region of chromosome 5 that involves genes that facilitate cell-to-cell communication -- CDH9 and CDH10 was named. Other genes claimed to be involved in brain development and cell-cell interaction in the nervous system were also suggested to be potential candidates. More report from the traditional view point here.
However there are serious limitations to the interpretation of these findings.
The mentioned genes have not been identified and proven to be related to autism in the studied subjects. A duplication, or single nucleotide polymorphism does not necessarily cause a phenotype. Futhermore, the genes mentioned makes sense within a paradigm of neurological brain development disorder but we should not forget that many of these genes, e.g. cadherins, CNTN4, ubiquitin actually also have function in regulating the immune system. If these mutations are genuinely related to autism, is that because they cause abnormalities of brain development or make the individual more susceptible to insult of an immune origin? This question can only be addressed in animal model, a “Knock In”, as we call it, which replaces a gene with a potentially “mutant” version of, it in the mouse genome.
Generally speaking though, even if a developmental gene, is involved in as little as 1% of the ASD population even with as little at 1% of the overall contribution, that would be an important finding. But the point is, should a study that identify plausible cause of a condition in only 1% of individuals and that requiring huge sums of money be conducted? Isn’t it a little bit like going to the moon? And what is that for? This is where one should look behind the scene, what are the true motivations behind these studies. Sorry to say, but it has, as often, little to do with science and health.
See article from Max Blaxill on the Age of Autism that deals with this issue:
True ethical prioritization in the research in causalities of autism comes with a full account its current features: Gene- environment- involving the immune system, the gut, the behavioral features of autism, and the regressive aspects of it.
Finding genes involved in immune regulation as well as brain function is potentially very interesting. Also, finding de novo mutations, definitely suggests some environmental factors at play.
True ethical prioritization in the research in causalities of autism comes with a full account its current features: Gene- environment- involving the immune system, the gut, the behavioral features of autism, and the regressive aspects of it.
Finding genes involved in immune regulation as well as brain function is potentially very interesting. Also, finding de novo mutations, definitely suggests some environmental factors at play.
Picture of Cadherin; A proposed candidate susceptibility gene.
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