It's not fully genetic; there seem to be some environmental factors also (for example, identical twins where one is autistic but the other is not. difficult child 3's Grade 1 teacher had one such set of twins). I did read the research paper, Janet. I took info from the post that mentioned it, then looked it up further. I actually posted right away, but something went awry with it, the site seemed to go down on me and I lost my post. Probably a good thing for people, I perhaps got a bit too detailed medically.
From what I could understand (and from what I recall) they have identified a location on the human genome, that is associated with various conditions such as schizophrenia, bipolar and autism. However, that seems to be as far as the connection goes. The fault in the genome at that point involves whether that location has too few or too many copies. In schizophrenia, there are too many copies. In autism, there are too few. I didn't find out whether this is on both chromosomes or only one of the pair. And how many copies too many (or too few) or whether that is connected to the severity of the condition, or if it's more like a jug overflowing - once it's overflowing, the floor is still wet, if you follow. But the jug can be ALMOST overflowing, and the floor just as dry as if the jug is only half full.
So I will need to read more. What is also needed, is to find where this research has been replicated (like the genes, I guess). Because I have also seen research (in other areas of medicine) which was loudly proclaimed as brilliant, as potentially Nobel-winning, which turned out to be junk research and unable to be replicated.
If a parent has bipolar or schizophrenia then (according to that research) they have too many copies of that patch of the chromosome. They pass the chromosome in question on to half their children (according to the law of averages). It is still possible that during replication of the germ cells (ie during meiosis) that crossing over reduces the number of copies of that section of chromosome. We know that a lot of crossing over occurs during meiosis, but you'd have to be darn lucky for it to cross over right there. Most crossing over separates more distant areas of the chromosome, rather than bits close together (again, law of averages - that's how they've mapped the genome).
So it would seem to me that it would be LESS likely for a parent with bipolar or schizophrenia to produce a child with autism.
However, a very important factor has to be considered, and it is very much related to what we are talking about here - the link between mental illness in the parent and in the child.
Is there a link?
Is the link causative?
If so, WHICH WAY is the link causative? Parent causing it in the child? Or child causing it in the parent?
And now we come to the important point - as adults, we have more control over what we do about it, who we take ourselves/our kids to see. If we are aware that WE have problems, then we are likely to be more enlightened about getting our kids seen to.
So an adult with bipolar (especially if it is controlled) is more likely to get problems in their child also seen to, and therefore diagnosed.
As a result - there is likely to be a greater level of awareness of mental health issues, and therefore a greater level of intervention and diagnosis, in the children of parents who have a diagnosed but well-controlled mental health issue.
The study you mentioned, Janet, was a very interesting one on the chromosomes themselves. It's an interesting topic and one I'd like to see studied more. It is only a fragment of the picture, however, because it doesn't explain everything; it poses more questions. What is also needed is an epidemiological study which looks at the rate of conditions such as autism and bipolar in the community in both parents and children, as well as other mental health diagnosis rates in parents and children (including siblings) and it needs to also be done randomly in the general population.
When we go looking for things, we usually find them. Sometimes what we find isn't what we were looking for in the first place. Sometimes we attach too much importance to what we find ("aha! THIS must be what I was looking for!") and either stop looking further, or consider ourselves justified in searching, when we actually may not have found anything relevant. Also, labels can change further down the track.
For example, I developed pain in my neck. An X-ray showed that I have vestigial ribs in my neck. My first reaction was, "aha! So THAT is what is causing the pain!" but then a doctor pointed to the narrowed space between the neck vertebrae and said, "Forget the ribs. They're not the problem. They're an incidental finding. What's going on, is nerve compression in your neck."
Another doctor said, "You've had that neck compression for years. Why would it only now start to cause pain? No, there is something else going on, in the soft tissues."
In other words, what we find may not necessarily be relevant. Just interesting. Maybe later on it may acquire relevance and we can re-visit the findings with better understanding.
But for now - I'll just sit here rocking in my corner...
Marg
laughing.
