Now THIS really *is* in the genes

This is a very cool publicity campaign, using — dare I say it — scientific literacy in an effort to raise awareness about some rare genetic disorders (full disclosure-time: my own family has one of them). Basically, next Friday’s date — 15/11/13 — neatly matches the chromosomal region (15q11-q13) affected by three overlapping disorders: Angelman Syndrome, Prader-Willi Syndrome, and Dup15q Syndrome (otherwise known as Chromosome 15q Duplication).

So, here we go, welcome to next Friday: International 15q Day!

Int 15q heading Europe

Awareness here is really important precisely because the three disorder overlap in ways that regularly cause confusion among physicians, including frequent misdiagnoses. And this is important because the non-overlapping features of the conditions can be quite striking, and the specifics of best-practice intervention will vary across them.

But, as I say, the really cool part of this campaign is the assumption that ordinary people will ‘get’ the principle of 15q11-q13. You see, you really can explain chromosomal disorders to people by referring to, well, chromosomes

And moreover, while these conditions are outwardly striking in terms of symptomology, their genetic basis is critical to understanding them scientifically. Without detracting from the importance of early behavioural and medical intervention with these kids, it is just as important to remember that understanding how these conditions emerge at a genetic level will, in the long term, help develop even better interventions, and even maybe some kind of ‘cure’.

While you're this far, check out these guys and their snazzy website
While you’re this far, check out these guys and their snazzy website

So, anyway, I nearly forgot to raise YOUR awareness. Here we go. Let me start with the geeky-chromosomal stuff. I’ll take it as near-general knowledge that humans generally have 23 pairs of chromosomes in each cell of their body, which collectively contain the genetic ‘blueprint’ from which their body develops. Scientists number the first lot of these from 1 to 22, with the 23rd pair being the X and Y chromosomes, which are often referred to as the ‘sex chromosomes’ because they determine the holder’s sex. Each time a woman and a man reproduce they pass on just one of each of the pairs of chromosomes to their offspring. This new individual has a unique combination of the genetic variations found in mommy and daddy (instead of being an exact replica of either mom’s or dad’s chromosomes). However, the child may also have new genetic variations – changes in DNA that occurred during the formation of sperm or egg but that are not found in other cells of mom or dad. These naturally occurring random differences can be of several types.

Essentially, the 15q11-q13 conditions arise because, at the point of conception, the copy of chromosome 15 contains a type of random change that affects the new child’s genetic blueprint in a particular way — a way that produces sets (or syndromes) of symptoms that society calls a ‘disorder’. Here is a graphical representation of the different ways mutations in chromosome 15 cause the three 15q11-q13 conditions.


For example, the light blue zone depicts the four ways that abnormalities in this part of chromosome 15 cause Angelman Syndrome. These are: chromosome deletion (where region q12 is not present); UBE3A mutation (where this UBE3A gene has mutated in chromosome 15); paternal uniparental disomy (where chromosome 15 contains two copies of dad’s chromosome 15, instead of one of dad’s and one of mom’s); and imprinting centre deficit (a bit of the q12 section is not the same as in mom’s). It is perhaps worth remembering that all humans exhibit lots of DNA-related mutations. It is basically a matter of luck whether our particular mutations lead to physical or behavioural features that cause us difficulty in later life.

Finally, not unrelated to their overlapping genetic origins, the three conditions also share overlapping symptoms. Here is another graphic, this time showing the ways these symptoms interweave.


All this is of interest not only because it helps scientists to understand the nature of the conditions themselves, but also because it helps them understand the way genes and chromosome are involved in ordinary physical development (i.e., by seeing how differences in chromosome 15 affect people with Angelman, Prader-Willi, or Dup15q, we can begin to understand what chromosome 15 actually does in everyone). You see? Science.

Go check out the International Prader-Willi Syndrome Organisation, the Angelman Syndrome Foundation and the Dup5q Alliance for more info, and maybe do the awareness campaign some justice by giving them a ‘Like’, +1, or retweet.

And do think of them next Friday…

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[Thanks to @aoifemcl for her advice on some particulars!]

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  1. Great post, Brian. It’s not an easy thing to explain, so I appreciate your insight!

  2. This is a great idea, however it is so important to clarify that the region affected is 15q11.1-13.2 and this implies that it is all of 15q11-13 that is duplicated. This can be confusing for families that are outside this range and may believe that all duplications on the 15q are included. The symptoms vary greatly for these other families as they are totally different syndromes. Rather than using an organizational name they should have used the correct name 15q11.1-13.2 Duplication Syndrome….

    • To Clarify better, we very much appreciate the insightful and informative article. Thank you for putting some much needed attention to these chromosome disorders. We would like to clarify and emphasize that when referring to the duplication of 15q, what is really meant is a duplication in the 15q11.1-13.2 region. There are many other duplications on the 15q that are not representative of the syndrome to which you are referring, which is appropriately named Chromosome 15q11.1-13.2 Duplication Syndrome not Duplication 15q. This is an important distinction as it has caused much confusion in our community with families that have a 15q duplication outside the 11.1-13.2 range. The misnomer has caused people to appropriate information that is not related to their disorder and use it when making medical choices for their children and philanthropic choices with their finances. Chromosome 15q11.1-13.2 Duplication Syndromes can come in multiple forms including the most recognized Idic15, Interstitial, Mosaic or others but it is distinct as a group from other disorders on the 15q. It is the former group to which this article applies and not the other duplications on the 15q.

  3. Mellissa Thurston

    Hi! This is VERY helpful.
    My question though…what if you have a 15q11.2 DELETION and not a duplication?
    How does that change the two visual charts, if any?

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