how genetic are ASDs?

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my uncle is believed to have some sort of autistic disorder. he is very logical, straight faced, insane number memory, compulsive, and is absolutely obsessed with politics. my dad is also very logical, not very emotional at all, and has milder forms of my uncle's symptoms.
and on the other side of my family, one of my uncles is believed to be schizophrenic, my grandpa was believed to be slightly as well, and my other uncle has severe ADD, but is absolutely tech savvy.

It is a wonder my immediate family seems so normal does this give me a high chance of having AS?

ASDs, mental illnesses, Rett Syndrome, like many health conditions have a genetic basis. Some of these health conditions are diagnosed at birth and others "turn on," like a switch, at a particular time for the individual.

could AS have switched on for me?

Autism spectrum disorders as a whole have a heritability anywhere from 90-97%; that is, any given case of an ASD will probably be about that much due to genetic factors and the rest to environmental factors (in this case, it seems to be very likely that the environmental factors have something to do with the way the genes express themselves).

What is very interesting is that ASDs in general, excluding Rett syndrome (the genetics of Rett's are different, but suffice it to say that Rett's is due entirely to genetics), tend to express themselves differently; so that if you were to calculate heritability with the entire spectrum, you get very-high-90s figures; but if you use only classic autism, you get figures more like 60% or thereabouts--that is, every case of classic autism is about 60% due to genetics; the rest is due to environment. They haven't done it with Asperger's, but it should be similar there. That points towards an interesting conclusion: Having an autism spectrum disorder is pretty much set down in stone from the time you're a zygote; but which kind of autism spectrum disorder you'll have can be affected strongly by environment. Apparently, before birth our neurological development is sensitive to environment; generally, things like good prenatal nutrition, an efficient placenta, being a multiple, mother's stress level, etc... We already know that kids with congenital rubella syndrome are more likely to be autistic; so a mom's illness could factor in, too, especially during those first three critical months of pregnancy. (Ironic, though, isn't it? If Mom takes the MMR shot, she decreases her child's chance of having autism by nearly eliminating the odds that her child will have congenital rubella syndrome...)

thats interesting. what's congenital rubella's syndrome?

Possibly. There are many genes thought to be involved in ASDs, and they work together with the environment (eg. wheter your mom smoked/drank during pregnancy, your birthweight, illness early in life and other suchfactors) to cause ASDs. Autism is not passed on in a traditional form of gene transmission (ie. autosomal dominant, autosomal recessive or X-linked), because so many genes are involved, so there is a very complex way in which the genes might be passed on in a family. Therefore it is possible to "hit" some family members and not others.

Again, environmental factors also play a role. Twin studies (where identical twins, who have exactly the same DNA, are compared as far as autism goes) have shown about 60% concordance (if one twin has autism, the other twin has a 60% chance of also having it). This points to a strong genetic link, but also to environmental factors; after all, if it were purely genetic, concordance would be 100%.

As for whether your family history is indicative for AS: of course AS is not diagnosed biologically yet, so if you have the traits the best way to find out is to get an evaluation from a psychologist/psychiatrist. They may sometimes ask about family history but sometimes they will just ask you to bring someone who knew you from childhood to make sure you had the symptoms early on, or ask you to recall your childhood yoruself, and they wont'care about your family. (in my case they didn't ask, but my father spontaneously mentioned some of his own traits and an evaluating psychologist even put it in my report that he looked a little autistic to him).

man, autism is so complicated, isnt it? it never ceases to fascinate. i feel like i cant take in all the information, though! >.<
i dont think i had THAT many signs early on. of course i didnt pay attention, nor did my parents. i do remember being a pretty secluded kid, who spent a lot of time alone willingly, and i had very narrow obsessions.

For me genetics all the way!
Not a doubt in my head.......it aint just hair and eye colour that determines genetics!

Among my family, cousins, aunts, uncles, grandparents..
You could prove the theory by us alone!
It's genetic. :p

I think most of the male relatives on my dad's side of the family could be on the spectrum. I am the only one with a diagnosis, though.

My mother's side of the family has most if not all the "strange ones" in the clan..

My son is dx'd as on the spectrum; my doctors agree that there is evidence of being on spectrum in my behavior and history. My parents each show weak characteristics, with my mother being the stronger exhibition of the two. I believe there is a genetic component, but not an exclusive causal relationship.


M.

It has polygenic inheritance, like height and skin color.
Likely, some of the genes are dominant and some recessive.

We call ALL those on the spectrum Jelibeans! It is kinder, friendly and easy to understand, we prefer it.
www.jelibean.com

For us it takes at LEAST ONE JELIBEAN to make a JELIBABY!! My mother, father, sister, grandparents, ex partners and now ALL children are diagnosed so I think together with a lot of you on here, we have almost proven that haven't we!

Embrace it, learn about it, deal with it and live a wonderful life! It aint all bad, FAR from it!

All our family have AS trait, someone more, someone less. We use to say "If they aren't mad, we don't want them". I think that AS is pretty much genetical, but I think that the difference between Aspe/HFA/LFA/etc. is mainly environmental. In my family we divide into "people who talked pretty early (6-7 month)" and "people who talked after 3 years", there are basically no medium measure and it seems pretty casual (for istance both me and my wife talked at around 6 month, our daughter is HFA and don't talk (apart from a few word) yet.

You pointed out rubella... we remember that we did rubella vaccine when she started talking at around 7 month, after that she completly stop for about 7-8 month. Could be a link? Is it possible that in the general population vaccine doesn't trigger AS but, if you are already AS they can trigger a particular AS kind? Is there any study about it?