Anything other than genetics?

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Looking at previous threads, the cause of AS for most seems to be related to genetics.

Anyone, else born very prematurely (weight and gestational age) and/or suffered a inventricular haemorrhage or any other sort of damage at birth?

Last edited by pixie-bell on 23 Oct 2007, 2:52 pm, edited 1 time in total.

everything has a genetic and environmental component.

often our genes predispose us to things... and fate or luck or what have you.... does the rest

Here is a tip of the iceberg list of environmental causes of ASDs:

Exposure to various hormone levels in the womb has been linked to both brain development and the index:ring finger ratio. At least one respected researcher is working on this angle. >> Baron-Cohen Studies

Another credible theory is that >> Disrupted Thyroid hormone levels in utero may change brain development and induce autism spectrum disorders. They mention a long list of possible thyroid disrupters, including dietary flavonoids, pesticides, medicines, etc.

Another theory is that >> Maternal immune activation can push brain development into an autistic pattern.

The idea that it is purely genetic is unproven. If any of these the many environmental theories are even partially true, then the purely genetic theory is wrong.

The fact that Autism is a spectrum condition ties in directly with the Gene theory. Example: with skin color you have 4 to 6 genes exhibiting incomplete dominance which allows for 64 to 256 different skin color phenotypes. It could easily be the same with autism. The fact that autism could be influenced by environment doesn't discount the genetic explanation provided that the environmental factors are mimicking the same genetic effects. Again, more sun will make your skin darker but skin tone is still a genetic issue.

AFAIK, nobody has ever said that it's purely genetic. From 1944 on, it has been noted over and over that it runs in families, and there are historical families from earlier periods that seemed to fit that pattern. But I don't think anyone claims that it's 100% genetics, or you wouldn't find any sets of identical twins where one was on the spectrum and the other wasn't, and yet that's relatively common.

Genetics is the closest thing we have to a proven cause, but that's not to say that other factors don't contribute, they clearly do. We just don't have much evidence about what the others are, how they work, or how likely they are to affect people who aren't somehow genetically predisposed.

I agree with the above posters--current evidence is inconclusive, yet suggests that ASD is caused by interaction between genetic and environmental variables.

In my case, I suspect that both genes and environmental factors were involved:

1) My mother and other family members show signs of AS

2) My ring finger is much longer than my index finger, indicating possible prenatal testosterone exposure.

3) My mother took antibiotics during her pregnancy

4) Apparantly, I suffered a head injury at 11 months of age.

5) I also had multiple high fevers at a young age. Fever has been shown to produce brain injuries with results ranging from depression to more debilitating conditions.

6) I grew up with emotionally unstable parents, causing me to be very withdrawn, and possibly exaggerating my AS traits. (Stress has been shown to exacerbate just about any medical condition, psychological, neurological, or otherwise.)

Good point about the twins. No one in the research community is saying it is 100% genetic, but that seems to be a common opinion on this board.

Look at some of the threads titled 'what do you think caused your ASD' and person after person says genetics; no one says an interaction of genes and the environment. And more than a few others here are critical of people that try to do anything to improve themselves or try to help affected children - again, there is a widespread assumption that it is purely genetic and that there is nothing that possibly could help. And the threads on 'should people with AS breed' also reek of a lack of understanding of the causes and the magnitude of the risk.

http://tuftsjournal.tufts.edu/archive/2 ... tism.shtml

"And among identical male twins, the chance that both are autistic is 50 percent."

This is completely compatible with the genetic theory of autism if you know anything about Epigenetics.

True, but much of epigenetics is not classical genetics (inheritance) - it is the switching on and off of genes and other phenomenon involving the expression of genes or alteration of phenotype, not their presence or absence. Teratogens (substances that cause birth defects) are often considered an epigenetic phenomenon.

If someone has the genes for resisting some disease, but they get turned off or suppressed somehow, that is different from someone that has a gene that predicts with certainty that they will get the disease. And what is responsible for those genes getting turned on or off? Often it is an environmental factor which changes the regulatory process.

If we wanted to look at it one way, we could say that all diseases are genetic. Rocks don't get cancer; bacteria don't get phantom limb pain. But that perspective isn't very useful. I'm not denying that there is a genetic component to ASDs (lots of evidence for that) - but there is no evidence that it is genetic to the exclusion of the environment.

I have seen the same fatalist opinions that some have here on boards for other conditions and diseases that I have. Some people believe that things are written in genetic stone so firmly that it is foolish to do anything other than accept things the way they are. Which in my case, turned out to be incorrect. I have been able to reduce symptoms (and go into remission) for several conditions by changing my lifestyle. I still struggle with some of those conditions (currently anxiety/panic disorder), but even there, I think that environment/lifestyle is important. Sure, I may have inherited some combo of genes that make me high strung. But there are things I know will make it worse, and things that reduce the dis-ease.

Last edited by monty on 23 Oct 2007, 6:00 pm, edited 1 time in total.

The reason I brought it up was because I am currently studying the developmental effects (infant -> adult) of individuals born prematurely and the conditions that can arise as a result i.e. NVLD, mood disorders, severe disability etc.

Yes, genetic and environmental factors do play a part, as do medical factors and prematurity (many studies to support this, if anyone is interested). And although I do have family members which fall on the spectrum (Dad, AS traits, cousin, autistic), I just wondered if anyone had thought about factors other than genetics/environment.

Pixie-bell.

Here's an interesting abstract on some of the things implicated in autism:

If oxidative stress is part of the ongoing developmental problems, that can be treated nutritionally. I'm not saying it will turned the autistic into NTs, but it may reduce some damage and make it easier for some people to cope with the day to day. Likewise, neuroimmunity might be able to be affected through diet and various meds that influence the immune system.