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To: neolib who wrote (176467)8/12/2020 9:15:16 AM
From: combjelly1 Recommendation

Recommended By
Terry Maloney

  Respond to of 359087
 
It is pretty clear there is better diagnosis. For a long time, the diagnosis only covered those who couldn't function without lots of help. What is now considered level 3. It used to be sort of a mystery that those with Asperger's, which is now part of level 1, did not show a bell curve as to intelligence, but heavily weighted towards the high end. It was eventually realized that the smart ones were able to develop coping skills and could camouflage their disabilities to some extent. Most of the "excess" diagnoses are one the level 1 and level 2 levels of severity which in the past would have been diagnosed as something else if it was ever diagnosed at all. And then there is the problem of diagnosing girls who tend to naturally be more social and the past were considered shy or bookish.

As of last count, there are something like 100 genes that are implicated with autism. Which means there are a lot of ways things can go wrong that are lumped under the category of "autism". Which goes a long way in explaining why the symptoms can be so varied and seemingly unconnected. Because they are.



To: neolib who wrote (176467)8/12/2020 10:42:44 AM
From: koan  Read Replies (1) | Respond to of 359087
 
I think it is just a complex issue. Probably genetics and environment combined????

I worked at the Stanford university autism research center for two years while in college in a work study program. Boy did they have the wrong theories in those days.

I got so used to the kids that when i went back into a normal class room I was shocked. But we had severe cases there. I saw a lot of "rocking" and special abilities.

I got used to the kids and tried to make them as comfortable as I could.

Here is some speculation:

theconversation.com

"A variety of genetic factors are likely to be the ultimate cause of most cases of autism. These may work by themselves, or in combination with environmental factors, to lead a child’s brain to develop differently and result in autistic behaviours

GeneticsTo examine the influences of nature (genetics) and nurture (environment) on a given human quality, scientists study twins.

To appreciate how these studies work, it’s first important to understand there are two types of twins. Identical twins share all of their DNA and, assuming they grow up in the same household, they will also share all of their environment. Fraternal twins also share all of their environment, but only around half of their DNA, just like non-twin siblings.

Twin studies start by defining a clear population, say the metropolitan area of a city, and finding as many sets of twins as possible in that area where one or both of the twins have the given trait of interest – in this case, autism.

Scientists then look at the “concordance” of that trait – that is, the percentage chance that if one twin has autism, the other twin will also have autism. If the concordance is higher for identical twins than fraternal twins, then we can say the difference is due to the increased amount of genetic material shared by the identical twins, and that autism is influenced by genetics.

Twin studies provided the first evidence autism may be genetic. Choku/Flickr, CC BYThe first twin study of autism was conducted in 1977 on 11 identical and ten fraternal twins across Great Britain, where at least one of the twins had autism. Concordance for identical twins was 36%, compared to 0% for the fraternal twins.

While the study was only small in size, it provided the first evidence that autism may be genetic in origin. Since this pioneering study, more than a dozen further twin studies have confirmed this original observation.

The best current estimate is that there is a 50-80% concordance for identical twins and a 5-20% concordance for fraternal twins. This indicates a strong genetic component to the condition. The figure for fraternal twins – 5-20% – also represents the chance of a couple who already have a child with autism having a second child with autism (referred to as the “recurrence risk”).

Once scientists have established that the cause of a disorder is influenced by genes, the next task is to identify the exact genes that might be involved. However, after several decades of intensive research, scientists could find no one genetic mutation that all individuals diagnosed with autism shared.

It was these findings (or lack of findings) that led scientists to stop thinking of autism as one condition with one cause. They started viewing it as many different conditions which all have relatively similar behavioural symptoms.

This new view of autism has proved extremely fruitful in discovering subtypes of autism. For example, a number of conditions have very clear genetic or chromosomal abnormalities that can lead to autistic behaviours.

These include disorders that have abnormalities of the chromosomes, such as Down syndrome. While no chromosomal condition itself accounts for any more than 1% of individuals with autism, when combined they account for approximately 10-15% of all individuals diagnosed with autism.

The exact genetic abnormalities that may lead to the remaining cases of autism are not completely clear. There are two reasons for this.

The first is that the genetic regions involved are likely to be very complex. Scientists have needed to develop new techniques to examine them.

The second is that it is probable the genetic mutations are very rare and complex. The DNA chain that forms our chromosomes contains more than 3 billion building blocks. To identify small pieces of DNA that may be linked to the development of autism among so many base pairs, scientists need to study a very large number of people with autism.

To date, no study has been able to examine the thousands of people necessary to identify with accuracy all of the small mutations that might lead to autism.



With more than 3 billion building blocks in the DNA chain that forms our chromosomes, it’s difficult for scientists to isolate genes that could cause autism. James Gentry/Flickr, CC BYHowever, with genetic technologies improving at an astronomical pace, as well as global scientific cooperation that will lead to large numbers of people being studied, major advances in the understanding of the causes of autism are likely in the very near future.

A likely prospect is that many cases of autism will be related to what is called “ common genetic variation”. This refers to differences in genes