How can genomics help us understand rare conditions?
In this explainer episode, we’ve asked Jamie Ellingford, Lead Genomic Data Scientist for Rare Disease, to explain how genomics is helping us better understand rare conditions.
You can also find a series of short videos explaining some of the common terms you might encounter about genomics on our YouTube channel.
If you’ve got any questions, or have any other topics you’d like us to explain, let us know on [email protected].
You can download the transcript or read it below.
[00:00:00] Florence: How can genomics help us better understand rare conditions? My name is Florence Cornish, and today I am joined by our Lead Genomic Data Scientist for Rare Disease, Jamie Ellingford, and he is going to be sharing lots more insights about the topic with us.
So, I guess before we begin, Jamie, it might be useful if you could explain what we actually mean by the term 'rare condition'?
[00:00:25] Jamie: Sure. Hi, Florence. So, a rare condition we define as something that impacts one in less than two thousand people, and so that's something that occurs really infrequently in the population. But we know that collectively there's lots of different rare diseases. And so, the estimates are that it's about one in seventeen people in the population that are impacted by some sort of rare disease, of which we think there's over seven thousand.
But research that uses data that we have here at Genomics England as well as other sources is starting to uncover more and more of these individual rare disorders. So collectively, as I just said, one in seventeen individuals, we think, is impacted by a rare disease, and that equates to almost three and a half million people here in the UK.
[00:01:15] Most of these rare conditions, we think, have a genetic basis, and perhaps we'll explain a little bit more about what that means.
[00:01:22] Florence: Yeah, no, it would be great to talk a little bit more about that actually. So as you said, most rare conditions we think have a genetic cause, but I think it might be helpful if you could explain what we mean when we say that something 'has a genetic cause'.
[00:01:35] Jamie: Of course. So maybe we go back to kind of the basics and kind of how a person is first formed. So, at that point of fertilisation, where the sex cells from mum and dad join, we inherit one copy of our genome from mum and one copy from dad, and it's the order and the composition of these letters in our genome which makes it unique to us.
Most of that genome is absolutely identical to anyone else in the human population. And a small fraction of it is unique to us and is a combination of things that we've inherited from our mothers and our fathers. And when we think about genetic causes, largely, we look at those differences. And so, what is it that's different in individuals compared to the wider population that could be driving these rare conditions?
[00:02:23] Florence: So could you maybe explain a little bit more about how people's genetic material, how people's genomes differ from one another?
[00:02:30] Jamie: So there's lots of different ways that we can observe these genetic differences. So some of them impact individual letters, and we, we may swap a single letter for another.
[00:02:41] We can also remove small sections, so it may be that a run of three or four of these letters is deleted from someone's genome. But on the opposite end of the scale, we can also see huge changes in how that genetic material looks.
So perhaps a good way to think about this is as a story. And so if our, if our genome is like any kind of good fiction story that you would read, then we can have spelling mistakes that impact single words,
[00:03:09] that impact whole paragraphs, or some which impact whole chapters. Lots of these different types of genetic causes can give rise to genetic conditions. And so even the smallest changes, the smallest spelling mistakes in words, can still give rise to rare genetic conditions.
[00:03:26] Florence: We actually have a previous podcast episode that explores that topic in a lot more detail. So if listeners want to check that out, it's called "Are genetic conditions always inherited from parents?"
So obviously, Jamie, we spoke quite a lot about DNA and genetic changes there, and this episode is all about how genomics specifically can help us better understand rare conditions.
[00:03:47] Um, but what actually is genomics as a field of study?
[00:03:53] Jamie: So simply put, genomics is the study of the whole genome, or at least as complete a picture of the genome as we can possibly represent. And so in the case of rare disorders, we use genomics to try and understand what the genome looks like from an affected child.
[00:04:12] And, um, in some cases, we're also able to look at the whole genomes of their relatives, so perhaps their mother and their father. And we use this information to best detect and best prioritise variants that we think are giving rise to their genetic condition. But how we've done that has evolved and advanced a lot over time, has gone hand in hand with these remarkable developments in technology.
[00:04:37] And so a decade ago, maybe 15 years ago, the state-of-the-art technologies were to look for single spelling mistakes or to be able to survey complete genes. Nowadays, we can generate data for the whole genome, and we can do that fairly cheaply, we can do it quickly. And we rely on computational algorithms and the development of bioinformatic resources to be able to properly make sense of that data. And so there's, there's three key aspects of bioinformatics, this discipline of integrating informatics, computational technology, with biology.
[00:05:17] And so the first is, having generated some data, can we appropriately find where in the human genome that data should map to? Having done that, can we detect these differences, these small or large changes in the human genome, for that individual? And finally, can we start to make sense of those changes? Can we understand whether they exist frequently in a population or they're unique to this family and predict what potential consequence they have on a gene's function?
[00:05:47] Florence: Mm. So there's obviously lots of different components of genomics, but how can all of them help us better understand rare conditions specifically?
[00:05:59] Jamie: So as we've already touched upon, most rare diseases have a genetic basis, and we think that that estimate could be something like 80% of rare diseases have a genetic component to them. And what we've seen over the past decade and further, is that genomics has really transformed the discovery of new genomic conditions.
[00:06:20] And so being able to look at data from the whole genome has allowed us to understand new genetic, types of genetic changes, changes in new genes, which could cause these rare conditions. And what we've seen recently is that move and that transformation from genomics as a discovery tool to a tool that we use routinely and so essentially, we've moved this technology from research laboratories into the NHS and the UK healthcare system. We've really come a long way, and so, whilst we see that the amount of genetic diagnoses that we can find is really dependent on the specific disorders, broadly, we find genetic diagnoses for somewhere between a quarter and half of the individuals that are referred.
[00:07:10] What that does mean is that there's still 50% of individuals out there that get referred to these services with a rare condition where we don't find an obvious genetic answer through the implementation of genomics within healthcare.
[00:07:24] Florence: Do you have, um, a specific example you could share of where genomics has had a real impact in our understanding of rare conditions?
[00:07:33] Jamie: So I think all of us that have worked in this space for, for a long time have our own individual examples. We're recording this in 2026, and over the past two years, there's been a flurry of discoveries of genes which don't directly encode proteins, that cause a certain type of rare conditions, and so we call these non-coding genes.
[00:07:54] These genes have recently been described as a cause of kind of wide neurodevelopmental disorders, as a cause of genetic blindness, and there's ten at the time of recording, distinct rare conditions another example that I wanted to elaborate on is something that was really personal to me because it happened really early during my development as a, as a researcher and as a, somebody who looks at genomic data very early in my career, and really kind of had a profound impact on how I think about genomics and how it can be applied.
[00:08:28] And so this was an individual who was referred with a certain type of rare condition. And through the analysis of their genomic data, we identified a genetic variant in a certain gene. At the time of testing, they were in their early teenage years, and when we looked at the scientific literature, what this suggested is that other symptoms were going to develop before the age of 20.
[00:08:52] And so at this point, genomic testing had been done in a really critical window for that individual and allowed them to be referred to specialist centres, and to be managed appropriately, and that's really ended up in a good outcome.
And what's becoming more and more frequent is the opportunity for genomics to inform enrolment to clinical trials, the development of targeted treatments, and we hope that in the next decade or so we'll see an increased flurry of those activities.
[00:09:22] Florence: Yeah. So I guess, would the headline be that genomics allows us to see changes in the genome that maybe more traditional genetic tests wouldn't have allowed us to see, and then that in turn helps us with our approaches to rare conditions?
[00:09:37] Would you say that that's accurate?
[00:09:40] Jamie: So it certainly gives us that opportunity.
[00:09:42] Florence: So I think we'll finish there, Jamie. Thank you so much for coming on, for taking the time to speak with us. It's been very insightful.
[00:09:50] Thank you very much. A pleasure to chat.
[00:09:52] Florence: If listeners want to hear more explainer episodes like this, you can find them on our website at www.genomicsengland.co.uk or wherever you get your podcasts.
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