tag:blogger.com,1999:blog-1892134081049774386.post4583088301872274218..comments2023-12-02T09:37:08.472-05:00Comments on Autism Jabberwocky: Ghosts of Autism Studies PastM.J.http://www.blogger.com/profile/12033918835169823548noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-1892134081049774386.post-45429734023790242362011-08-17T21:03:48.350-04:002011-08-17T21:03:48.350-04:00RAJ,
As I understand it, and I could easily be w...RAJ, <br /><br />As I understand it, and I could easily be wrong, heritable doesn't mean the same thing as inherited. As "random" mutation such as Downs can be highly heritable while not being inherited.<br /><br />So, while you wouldn't expect DZ twins to both have Downs (although it would occur at the same rate as other siblings), you would expect that is be a good chance that the mutation that causes Downs could be passed to any potential children.M.J.https://www.blogger.com/profile/12033918835169823548noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-91818257521536396332011-08-17T07:56:59.176-04:002011-08-17T07:56:59.176-04:00It is the early European twin studies that led to ...It is the early European twin studies that led to the notion that autism is the most 'heritable' of the developmental disorders.<br /><br />The idea that you can calculate a 'heritability' estimate by the difference in concordance rates between MZ and DZ twins can't explain Downs Syndrome which is caused by a de novo mutation (Trisomy 21)and is not inherited.<br /><br />In Downs Syndrome, which is also associated with high rates of co-occuring autism, all MZ are concordant for Downs Syndrome and all DZ twins are discordant for Downs Syndrome.<br /><br />Calculating a 'heritability' estimate for Downs Syndrome would make Downs Syndrome, not autism the most 'heritable' of the developmental disorders which is throwing all logic and reasoning out the window.RAJhttps://www.blogger.com/profile/17686665037607780553noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-47816205927549435662011-08-16T07:53:34.901-04:002011-08-16T07:53:34.901-04:00If there is an environmental influence that is cau...If there is an environmental influence that is causing the increase and the numbers are actually growing, then the ratio remaining the same makes sense.<br /><br />But, for example, if a large cause for the increase was the expanding/changing definition of autism then I am at a little bit of a loss to explain how the ratio could be preserved.<br /><br />Think of it this way, I start out by saying that only apples are fruit and notice that most are red (4 to 1 ratio). A few years later I decide to exapand the definition and start calling pears fruit as well. A few years after that I include organges. Would you still expect that 4 to 1 ratio of red to non-red to be there?M.J.https://www.blogger.com/profile/12033918835169823548noreply@blogger.comtag:blogger.com,1999:blog-1892134081049774386.post-41785933221158651102011-08-16T05:27:27.663-04:002011-08-16T05:27:27.663-04:00Aren't boys more susceptible to terratogens? ...Aren't boys more susceptible to terratogens? I don't recall the reasoning...Usethebrains Godgiveyouhttps://www.blogger.com/profile/05026223483117357541noreply@blogger.com