tag:blogger.com,1999:blog-1892134081049774386.post5100736030538312842..comments2023-12-02T09:37:08.472-05:00Comments on Autism Jabberwocky: Genetic Mutations in Autism - Cause or Effect?M.J.http://www.blogger.com/profile/12033918835169823548noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-1892134081049774386.post-33875583513996642242010-11-21T21:47:43.599-05:002010-11-21T21:47:43.599-05:00Rebecca,
Thanks, I'm happy to hear that you f...Rebecca,<br /><br />Thanks, I'm happy to hear that you find my site interesting.<br /><br />Regarding the genetics of autism, I think it is safe to say that whatever is going on, the genetic pieces of autism are not going to be simple. <br /><br />One one hand you have these rare mutations that seem to give you a greater risk of autism and on the other you have recent results like <a href="http://bit.ly/b0Q9Ih" rel="nofollow">this</a> that seem to say that the problem might be more about the expression of the genes rather than the genes themselves. <br /><br />And then you have the idea that if there were a single mutation that caused the majority of the cases of autism it should have been found by now.<br /><br />Putting all of that together leads to one big, fat question mark.M.J.https://www.blogger.com/profile/12033918835169823548noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-69860661364591430442010-11-21T14:29:51.170-05:002010-11-21T14:29:51.170-05:00It's an interesting idea, that the variations ...It's an interesting idea, that the variations are chickens and not eggs... but I think Jonathan makes a good point about individual differences within ASD. As I'm sure you know, genes rarely influence behavior directly, they can only turn on and off production of proteins. One recent study demonstrated that the "high risk" variation in CNTNAP2 influenced the development of neural connectivity in the frontal lobe and other areas related to attention and processing. This gene has been associated with increased risk of autism (and other developmental and communication disorders), but subclinical symptoms also appear in individuals who have no diagnosis. This is likely to explain why some siblings have subclinical symptoms without meeting any of the other criteria. <br /><br />Anyway, I think this suggests that the influence of genes cannot be considered without considering the dynamic interplay between different genes, prenatal and postnatal environment, which includes exposure to teratogens and physical experiences that influence connectivity in the brain. Add additional complexity by introducing the variable of timing, and you've got a recipe for an infinite number of individual variations (even between otherwise genetically identical twins). <br /><br />What's awesome about this, as you suggested in your comments, is that thinking about this as a dynamic process, one can, in theory, be modified through well orchestrated experiences! <br /><br />(By the way, thank you for your blog. It's a fantastic combination of science and personal perspective.)Unknownhttps://www.blogger.com/profile/08416305086558713110noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-87038456015231519702010-09-25T16:27:33.412-04:002010-09-25T16:27:33.412-04:00Author,
I think the genetic studies do serve a pu...Author,<br /><br />I think the genetic studies do serve a purpose, although part of that purpose is to feed the academic process. Publish or perish.<br /><br />Another purpose would be that researchers get to chance to play with some of the cool new scientific toys instead of the old boring ones.<br /><br />But seriously, these studies are showing that our ideas about autism are wrong. These studies are showing that autism is not primarily a genetic disorder and are pointing towards the fact that there is some sort of process, ongoing or one-time, that is "causing" autism. <br /><br />But since we have no real idea what that process is, we can either spend money on the psych 101 style research (how does looking at this picture of a cartoon face make you feel) or we can spend it on genetics and possibly get lucky when we find a biological pathway that is disrupted.M.J.https://www.blogger.com/profile/12033918835169823548noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-74468744726342797352010-09-25T16:13:54.426-04:002010-09-25T16:13:54.426-04:00Jonathan,
I don't know whether sample size wo...Jonathan,<br /><br />I don't know whether sample size would play that much of a role. There have been several studies recently were hundreds of people with autism were involved and that should have been sufficient to find anything that a sizable percentage of them had. <br /><br />I would say that one possible confounder would be the idea that there are many different subtypes of autism and each would have its own genetics. It might be hard to see an effect if the each subgroup only made up ten to twenty percent of your sample.<br /><br />Which goes into your second point, would you expect the strengths and weaknesses of autism to be determined by genetics? My twins are very similar in some features of their autism but complete opposites in others. Assuming that they share the same underlying cause of autism, how and why could they differ? There is nothing about their individual mutations that could explain the differences. <br /><br />Why can one not tolerate noise while the other seeks it out? I realize that the behaviors are two sides of the same coin but presumably there are differences in how their brains work that are causing them to behave in opposite ways. <br /><br />The only explanation I can come up with is that the specifics of autism are not controlled by genetics and takes me to the idea that autism is an ongoing disruption like Fragile X and less like something like Downs. But unlike Fragile X, there is no known common genetic variant which suggests that the disruption isn't limited to a single biological process like it is in Fragile X.<br /><br />In a way this is good because it should be easier to correct problems that aren't written into the genes. But on the flip side it is worse in that we have to find the disruptions unique to many different subtypes of autism.M.J.https://www.blogger.com/profile/12033918835169823548noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-90584173902037458152010-09-25T09:06:20.268-04:002010-09-25T09:06:20.268-04:00It is a legitimate and an interesting question to ...It is a legitimate and an interesting question to ask.<br /><br />I ask another, whether all of these genetic studies are providing any useful information at all, or are they merely feeding an industry of academic publication and justifying various university departments existence in terms of the funding they attract?<br /><br />No that's two questions I will come in again :)Larry Arnold PhD FRSAhttps://www.blogger.com/profile/05074432718592268750noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-63378523179114138432010-09-24T12:33:49.560-04:002010-09-24T12:33:49.560-04:00I agree with your observations.
I still think vacc...I agree with your observations.<br />I still think vaccines are the culprits. The toxins in vaccines, particularly mercury, can cause mutations.needle.and.damage.donehttps://www.blogger.com/profile/09968831918601346611noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-51857438228762242452010-09-24T11:57:08.461-04:002010-09-24T11:57:08.461-04:00two issues here:
1. From what I understand, one o...two issues here: <br />1. From what I understand, one of the problems with genetics research in autism is lack of sample size. To date, it has been infeasible to get enough subjects in studies to find more genetic defects that can cause autism. <br /><br />2. Autism is probably a term to describe a variety of different conditions with somewhat similar (though not identical) phenotypes, so it is unlikely that one common pathway genetic type of cause will be found in autism. For example, I have above average or even superior skills (in vocabulary) that Stephen Wiltshire is deficient if not retarded in. Wiltshire is a savant in drawing. I have very serious fine motor impairments and am basically retarded in drawing and have printing that is not entirely legibile and is difficult for me in handwriting. I do poorly on block design and object assembly tests on wechsler that many others with ASD diagnosis do well on. Yet we have the same diagnosis, but clearly a different disease. <br /><br />It is possible you are correct about some cases of autism due to the phenomenon of epigenetics in that something could have happened to alter the genes that might be a side effect. <br /><br />I knew there was a large difference between fraternal twins and non twin siblings, but I was not aware that it was as large as you said. <br /><br />Some cases are inherited via autosomal dominence such as tuberous sclerosis. They have found abnormalities on chromosomes such as 22 such as in DiGeorge syndrome which is associated with autism. Some cases arise from spontaneous mutations. So you could be right in some instances about autism but not all.jonathanhttps://www.blogger.com/profile/14972394536850151087noreply@blogger.com