Down Syndrome – Autism – Rett Syndrome

Down Syndrome – Autism – Rett Syndrome

17th October 2018

Back in 1996/97 I’d realised that my son and I had significant issues that other autistic people didn’t have. There were things we had in common and many more that we didn’t. I needed to find the answer for those issues that weren’t part of Autism. It was at that time I was briefly in contact with a lovely young man, who, along with Down Syndrome was also diagnosed with Autism. Strangely, of all the autistic people I read online, this young man was the person I most related to. But for him of course, he was also dealing with Down Syndrome issues and although we had difficulty communicating in certain respects, he was extremely intelligent and articulate and spoke of some of his concerns about ‘brain tangles’ which he explained was an issue for some people with Down Syndrome when they get older.
I was so touched by him that I decided when I found the answer to my son Sean’s and my issues, I’d research Down Syndrome. The little that we corresponded had allowed me to understand that there was a great deal to Down Syndrome, much more than I had previously understood. Having Down Syndrome and Autism together is also very different than Down Syndrome on its own and I realised that he was in two worlds in a sense.

In August of 1997 I bought a book from Amazon titled: ‘Autism and autistic-like conditions in mental retardation’ by Dirk Kraijer. I had difficulty reading it at that time and I’m aware Mr Kraijer would understand why, but I noticed there was a segment about Down Syndrome and I looked at it and noticed the author had stated that ten percent of people with Down Syndrome also have Autism. That statistic struck me, being a higher percentage than in the general population, so to my mind this was noteworthy. And that statistic has stayed in my mind ever since.

Years ago, when I looked up a site about Down Syndrome for the genetic basics, it explained that Down Syndrome occurred due to an additional copy of chromosome 21 (Trisomy 21). Another way it occurred was due to part of chromosome 14 breaking away and attaching to chromosome 21, and on rare occasions, familial inheritance. I didn’t want to delve too deeply at that time as well because I was very fond of my friend and I felt odd about doing so. There will likely have been new information from research studies since that time, I realise. In the very near future, I hope to catch up with that information and now study Down Syndrome at length, along with a group of other disabilities.

Regarding Down Syndrome, my question since that time has been, what causes this significant chromosomal change and why does Autism affect a sizeable group of these folks? Something I would like to check is the X chromosome. I have a suspicion that an issue on the X chromosome is one of the precursors to the chromosomal errors of 14 and 21 in Down Syndrome. I should also like to know if there are any families where there is more than one child with DS while also having a sibling/s free of DS. Such a family or families could greatly assist. If I am correct, although it would be rare, this must have occurred. Further, the family where a sibling without DS has themselves gone on to have a child with DS or a pregnancy. And though this would also be rare, I suspect this too must have occurred.
I suspect Down Syndrome will have several contributing components causing the chromosomal changes. Once I study this condition at length I’ll have more information to work with, but for now my focus is the X chromosome. Other important aspects are which X chromosome the individual with DS has, (including determining that of siblings’ X chromosome without DS) and when applicable, XCI pattern.

There is a group of genes I believe to be on the X chromosome that maintain records of pregnancies, so to speak. They contain ancestry records which in part prevent the same dna occurring twice. I believe one of this group of genes is contributing to DS.
By Fiona MacLeod © 2018
To be continued….