Highlights from the World Congress on Endometriosis 2014

It’s that time again, that time when the best and brightest in the field of endometriosis gather together in one place to share their collective experience and figure out where the future of endometriosis research and treatment is going; all whilst enjoying a caipirinha on the sunny beaches of Sao Paulo (us science types know how to multitask). Although I managed to go to the previous WCE in France, unfortunately I couldn’t make it this year, so instead of enjoying the glorious heat of the Brazilian south I was enjoying the drizzly rain of the English northwest, oh well. However, thanks to a friend, I did manage to get the book of abstracts (which is basically a summary of all the talks, presentations and posters at the conference) so I can give you a rundown of what’s been going on in the field of endometriosis research now and in the future.

Before I continue I must mention that the information I’ll be presenting here is taken only from the abstracts, which as basic summaries of the research and not in depth discussions and may or may not be taken from completed or peer-reviewed research. Also because these are conference papers I can’t provide links to source material as I normally would.

To start with, just looking at the book is encouraging, over 400 pages of research into all the many and varied aspects of endometriosis, which is broken down into different subject matters, so I’ll start with genetics and endometriosis.

Genetics is an important factor in endometriosis, mainly because we don’t really fully understand how genetic changes contribute to endometriosis risk. A team from Sweden aimed to examine indirectly the role genetics play, by looking at the rate of endometriosis in twins. There are two different types of twins: monozygotic (where both twins come from the same egg and are essentially genetically identical) and dizygotic twins (where each embryo comes from a different egg and can so each twin can be very different from the other). Of all the female twins this research looked at they found that there was a much higher risk of endometriosis if your monozygotic twin also had endometriosis. That certainly seems to suggest that genetics plays a role in the origin of the disease. Of course there are other factors at play too in determining endometriosis risk. This team, after doing some calculations, found that in the women they studied, genetics accounted for around half of the risk associated with endometriosis and environmental factors accounted for the other half. Finding out what the specific genetic and environmental factors are and how they increase or decrease the risk of endometriosis, is an ongoing challenge for the future.

Several other studies presented at the conference aimed to find out what these genetic factors are. Our genetic material (our DNA) is a funny thing, it can change in many different ways, some bits can swap, duplicate or be deleted all together and sometimes specific changes can be associated with specific diseases. Other research identified some of these specific changes associated with endometriosis which may, in the future, might allow us to identify women at risk of the disease with greater ease and hopefully give us to better understand the way in which the disease works.

Of course there are problems to consider, for example, are the genetic changes we see the same across all women? One of the presentations from an international team found that the genetic changes we know of so far are very similar between women of European and Japanese ancestry, but we still have no information on women of African, Chinese, Indian etc ancestry to compare them to. These types of studies though require a great deal of time and money invested in them, so it may be a while before we see a complete picture of the genetic risk associated with endometriosis for women across the world.

Another point to consider is the difference between types of endometriosis. One piece of research from a Danish team found genetic alterations specific to deeply infiltrating endometriosis. Therefore it could be that peritoneal, deeply infiltrating and ovarian endo all have different genetic alterations (and different genetic risks) associated with them. It’s good to know though there are people actually looking into this and one day, maybe soon, we’ll have that complete picture.

More to follow soon.

In the Genes

I recently read, with great interest, several stories (also here) about a new study into the genetics of endometriosis published by an international research effort based in Australia (better summary here). Most of the news items centred around a headline involving an announcement like ‘new genes linked to endometriosis’, or something along those lines. As my background is in human genetics I was keen on looking up the study at the centre of these reports. This particular study (link to abstract here) was looking at what gene/s may be related to endometriosis in women of Japanese and European ancestry. This was quite a large study as well, including 4,604 women with endometriosis and 9,393 controls, a far greater number of any other such investigation. 

Lots of studies on the genetics of endometriosis have been done in the past, mostly with slightly disappointing results. This is mainly because we haven’t yet been able to find a genetic link to endometriosis that is common amongst all women of all races.

But before we go any further into that study, or its results, I think I should go over some of the basics about why genetics is important and why we should bother looking for endometriosis related genes.

Let me ask you something, when an item in your house (Like a fridge, cooker or energy dispersive x-ray diffracter, for example) malfunctions what is the first thing you do? If your answer is “buy a new one” congratulations, you have more money than me. But we less monetarily endowed people tend to look at the instruction manual to try and figure out what’s gone wrong. The human body is similar in that way, because we too, have an instruction manual and that manual is called our DNA. 

This stuff - Image courtesy of Freedigitalphotos.net

 DNA is a long, twirly, helix like substance found in nearly every cell in your entire body, it’s the set of instruction that made you. But DNA isn’t written in any normal alphabet, no the DNA alphabet is written in an alphabet consisting of only four letters (A,T,G and C) which make up words, some thousands of letters long,  which we refer to as ‘genes’. Each gene codes for making a certain protein and there are tens of thousands of genes in your DNA instruction manual making almost one hundred thousand proteins.

That’s all fine and dandy, but when a cell divides it has to copy every single letter of the DNA manual, all 3 billion letters, and your cells have divided many, many times before you are even born. So, despite some astonishing cellular proofreading, errors start to creep into your DNA; most are harmless, rarely they are beneficial, sometimes they are harmful (we call these errors ‘mutations’). If these mutations occur in a gene (or number of genes), it can corrupt the way the protein product of that gene functions, hence causing cells to behave in odd/dangerous ways leading to, what we know as, a disease. So when a disease occurs in a group of people, we can look at their collective DNA to see if they share any common mutations.

This is what the aforementioned study was looking at: common mutations in DNA amongst women with endometriosis of European and Japanese descent; this would hopefully allow us to begin picking apart how and why endometriosis arises in some women and how it is passed on through generations. Mutation comes in different types though and the particular mutations this latest study was looking for were called SNPs (which stands for Single Nucleotide Polymorphism, not Scottish Nationalist Party, for all our Caledonian readers). This type of mutation is when only a single letter of your DNA is changed and, though you wouldn’t think changing one letter out of 3 billion would make a difference, it can have wide reaching implications.

Anyway this latest study found several of these ‘SNPs’ that were common amongst women with endometriosis. Unfortunately they all have terribly unmemorable names, such as ‘rs12700667’, ‘rs7521902’, ‘rs13394619’ and ‘rs10859871’, but who cares because now they’ve found these mutations, we can start getting a better understanding of endo leading to better diagnostics and treatments right? Well, yes and no.

One of the troubles is that, unlike some diseases which are caused by a mutation in a single gene, endometriosis is related to mutations in lots of different genes (what we call, polygenic). Now the more genes you add to the picture the more complicated it becomes because you have to take into account the function of each gene in the wider context of the disease. This information will eventually offer us some great insights into how endometriosis works, but figuring out all the connections may take some time. 

This, for example, is the interaction network for just ONE gene: Source - Wikipedia

There’s another issue as well, genes aren’t the only thing DNA is made of - far from it.  You see, genes make up only around 2% of your DNA, so what is the rest of it there for? For a long time it was thought the DNA that didn’t have genes was just ‘junk’, it had not function, a remnant of our evolutionary past and graveyard of ‘dead’ genes.  However, recently we have come to understand that this ‘junk’ DNA has a lot of other, very important, things lurking in it. Some of these things act as ‘switches’ for genes, basically controlling whether a gene is on or off inside a certain cell. So it’s not just about the function of a gene, but the regulation of it as well.

In this latest study, several of the mutations they identified weren’t in genes at all, but were instead found in DNA around them, which unfortunately complicates the matter further because now we have to figure out what implications this has on gene regulation as well as function.

So, where are we at the moment? The diagram below shows where we are and how far we have to go before we have a complete understanding of endometriosis. 

Simple as that!

Although we are far from understanding endometriosis in its entirety, studies such as this latest one have opened the door and pointed the way forward for us. It’s going to take more time and a lot more effort, but then, nothing worth doing was ever easy.

In the news this week

You may have seen, in one of the many news outlets that have reported it this week, that there has been a major story in endometriosis. This is the story concerning the finding of a new genetic locus associated with endometriosis (if you’ve not read it yet, there’s a good report here).

But what does it all actually mean? Well let’s start at the beginning. Several groups of researchers from the US, UK and Australia have been looking at why some women get endometriosis and other don’t. As endometriosis runs in some families the best place to look is at your DNA. Your DNA is like the set of instructions that makes you, and even though you share around 99.99% of your DNA with any other person on this planet each person’s DNA is individual in some way. If you imagine your DNA as a book, it is divided into 23 ‘chapters’ we call chromosomes. In each chromosome we have hundreds, sometimes thousands, sets of instructions for making proteins, each instruction we call a gene. However, the instructions sometimes get corrupted which is what is known as mutation. A mutation in a gene (or set of genes) can cause it to stop working properly which can be bad news for your body as it can lead to cells going haywire and causing disease.

This is what we think happens in endometriosis, mutations occur that make certain cells behave in an unusual manner leading to disease presentation. The only trouble is finding the mutation/s responsible is a daunting task, a task that was taken on by the collaborative research team mentioned above. What they did was to look at the DNA of women with and without endometriosis and look for any errors common only to the women with endo.

What they found was a particular genetic variation on chromosome 7 that was associated with an increased risk of developing endometriosis. The trouble is the variation they found was not in a gene. If we go back to our analogy of DNA being like a book with instructions in, most of the ‘text’ in our DNA book is actually just rubbish that doesn’t contain any useful instructions (what is known as an ‘intronic region’), this is where the researchers found their variation, in a region dubbed, rather unpoetically, rs12700667. However, sometimes variations in these ‘rubbish’ regions can give us clues as to where to look for genes that are involved in endometriosis. For example, the authors of the paper identified two genes of interest, named NFE2L3 and HOXA10, in the abstract. HOXA10 is particularly important in this case as it is a major controller for the development of the uterus.

So what does this mean for endo patients? Well unfortunately it’s unlikely to will lead to any new cures or diagnostic methods anytime in the near future. What it will do though is help us better understand who is at risk from the disease and why is it passed along some family lines.

The original research was published in Nature Genetics, you can buy the full text article or view the abstract free here.