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A Genetics Special

How genetics and gene therapy could hold the key to future breakthroughs in treating sight loss.

In this special programme, we examine the role genetics plays in both the inheritance of sight loss and its future treatment. We hear about the latest breakthrough reported in the journal 'Nature Medicine' in which the vision of a completely blind man was partially restored using light-sensing proteins first found in algae. He was treated with a type of therapy called optogenetics, which uses the proteins to control cells at the back of his eye.

And we discuss the merits of gene testing with the Chief Executive of Retina UK about how genetic testing can help people with inherited sight loss make future choices about their lives.

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19 minutes

Last on

Tue 1 Jun 2021 20:40

In Touch Transcript for Programme 'A Genetics Special' broadcast Tuesday 1st June 2021

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IN TOUCH – A Genetics Special

TX:Ìý 01.06.2021Ìý 2040-2100

PRESENTER:Ìý ÌýÌýÌýÌýÌýÌýÌý PETER WHITE

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PRODUCER:Ìý ÌýÌýÌýÌýÌýÌýÌýÌýÌý SIMON HOBAN

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White

Good evening.Ìý Tonight, we’re devoting the whole of the programme to a discussion about genetic testing and its role for people who are blind or partially sighted, as the result of an inherited condition.Ìý I should say, right from the start, don’t expect a full-on course on genetics, it’s a very complex subject and we’d probably have to take over Radio 4 for a month to do it.

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What we want to concentrate on is, as I say, genetic testing, what it can tell you about your own condition and the likelihood of you, or other members of your family, inheriting it or passing it on.Ìý It’s something all of us with a congenital eye condition have wondered about but our understanding and awareness of the importance of genetics varies quite dramatically.

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Two years ago, we interviewed Retina UK, a charity which works with people with inherited sight loss, who were doing a survey about this.Ìý The results of that found 43% of people weren’t aware of genetic testing or that they were aware of it but thought it wasn’t available to them.Ìý That led to Retina UK setting up a new part of its website dedicated to genetics and helping people with some of the big decisions around genetic testing.

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Well, Tina Houlihan is the Chief Executive of Retina UK.Ìý Were you surprised by that result, only slightly less than half of the people that you talked to, not even aware of testing?

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Houlihan

A lot of what our insight survey gave us in 2019 was surprising, considering that this group of conditions are all genetic and all inherited.Ìý I think what is important to add is that in addition to a lot of people not being aware or not being aware that this service is available for them, that we estimated as far as 15% of our community can actually name the gene associated with their sight loss.Ìý So, we knew there was an area that we really needed to work on and help inform the community about genetic testing and counselling.

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White

Okay, let’s do some simple science then, before we bring in our other two guests, because there are, I think, three basic types of inheritance when it comes to eye conditions.Ìý Can you explain those as simply as possible, just so we know what we’re talking about?

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Houlihan

Yes, so, there are several different types of inheritance patterns.Ìý There are autosomal dominants and autosomal recessive, which means you either need one copy or both copies of that particular gene to have a defect on it.Ìý There’s also x-linked conditions as well, which are a different type of pattern.Ìý I think, moving forward, we have to understand that this group of conditions is infinitely complicated.Ìý There are at least 250 different variants of genetic diagnosis and we know that that’s going to grow.Ìý So, we know it’s an extremely complex area and it is something that we’re hoping that we can break down into helpful simple information for the community, to know exactly where they stand with their genetic condition.

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White

And just to take one of the assumptions that’s often made or that you often hear about these kinds of conditions, which is that they’re sex or gender related. ÌýThey aren’t all, are they but can you just say something about that, just so that we’ve got a basic handle on what the variations are?

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Houlihan

I think that with x-linked retinitis pigmentosa there is a lean towards the female being the carrier of that defect and a male offspring actually having the symptoms of that.Ìý I think that for further information on your familial patterns, going through the process of genetic diagnosis and genetic counselling will help you have an independent understanding of your individual circumstance.

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White

Okay, let’s bring it down to real people and what it means to them.Ìý We can speak now to Martin Hills and Bavini Macquana [phon.], both of whom are living with the inherited condition retinitis pigmentosa.Ìý Bavini, if I can start with you, just tell us a bit about your own situation and what part inherited sight loss plays in your family.

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Macquana Ìý

I’ve been registered with retinitis pigmentosa at the age of 17 and, if I’m honest, it was a complete shock.Ìý So, nobody in my family has been diagnosed with sight loss, we hadn’t even heard of the condition when I was diagnosed.Ìý So, up until now, 23 years later, I’m still the only one with retinitis pigmentosa in my family.Ìý So, right now, I only have 1% remaining in one eye, so I can only see light and dark.

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White

Okay.Ìý Martin, what about you, what’s your family situation?

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Hills

Right, a little bit different to Bavini really, Peter, because there is RP in our family structure, in fact now there are four generations of it to below me, all with some indication of RP and some of the cousins, etc., aren’t.Ìý So, in my particular case it’s a 50/50 chance every time.Ìý But fortunately, I’ve got a very slow deteriorating sight loss and I’ve been able to have a fulfilling career and I’ve still got a pretty reasonable amount of central vision but I’m afraid my periphery is absolutely rubbish.

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White

So, Bavini, how did you come, therefore, to take a genetic test, what made you do it, since you said you’ve had this for – what – 23 years or known about it for 23 years?

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Macquana

Yeah, so about four or five years ago, at my annual Moorfields Eye Hospital appointment, it was mentioned to me.Ìý I had a number of questions that just kept building up over the years, that simply couldn’t be answered.Ìý Questions like:Ìý How have I got this?Ìý Why me?Ìý What’s it going to mean for my daughters?Ìý I’ve got two young girls.Ìý So, it was offered and explained to me what genetic testing is and, of course, what genetic counselling is.Ìý And I was asked the questions whether I would like to take part and yeah, I – learning how it could support and answer those questions I definitely took part.

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White

Because it sounds as if you didn’t get any genetic testing before deciding to have your children.

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Macquana

No, definitely not.

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White

So, it just wasn’t the kind of thing that even occurred?

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Macquana

No.

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White

No.Ìý And Martin what was your motivation for this, given that you say that you haven’t, as it were, got it that badly and it hasn’t occurred, clearly, in your family, so what made you want to get tested?

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Hills

Really I was officially diagnosed in 2003 and, let’s face it, I don’t think genetic testing was around then.Ìý I only really started to get interested when I started volunteering for Retina UK, where I learnt an awful lot more about it and decided to go for it and see where I could go with it, particularly for the benefit of our wider family because I think it matters.

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White

So, that was – you really want people in the family to know what the issues are because, in a way, it was a bit late for you, if I can put that rather crudely, wasn’t it?

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Hills

Yes, that’s quite true.Ìý But, in fact, they haven’t discovered the problem gene for us yet.

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White

How difficult was it to get the test, Bavini, for you?

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Macquana

To be honest, I think it was quite easy.Ìý I spoke to a genetic counsellor and there and then my blood samples were taken, because I don’t live in the same town as my parents it was posted out to them, they had to then carry out their blood tests and have it sent back.Ìý So, that was approximately six to eight weeks.Ìý It was then waiting for the results, which took about nearly three years.

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White

Three years – which is a long time to wait for the information.

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Macquana

It is.

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White

And what’s it actually told you and what difference has it made to how you’re thinking about it and presumably what you’re telling your daughters?

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Macquana

Yeah, I mean, they’ve been able to identify exactly what gene it is that’s causing my retinitis pigmentosa and it is one of the rarest ones.Ìý So, when I was told about four years ago now, I was one in a family of 10 that had been diagnosed with this one.Ìý But what it means is that I – as long as my daughters’ potential partners get tested and they’re not carriers, it’s very unlikely that RP will progress further down the family tree.

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White

So, that is a question, in a way – this is where it gets tricky, doesn’t it, in human terms – that’s where your daughters will have to say to partners do you mind getting tested because this is an issue.Ìý Yeah.

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Macquana

Well, yeah, but to be honest, they perfectly understand why, they’ve attended so many things with me with Retina UK and they sometimes tell me, this is the information and this is what they’ve got to do.Ìý So, they completely understand it.

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White

Martin, what about you?Ìý It won’t have made any difference to the decisions, perhaps, that you make but what’s been the result of you undergoing this testing – what do you know that you didn’t know before?

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Hills

Well, the thing I don’t know is which my problem gene is, at the moment, but there’s some exciting developments going on and very recently a paper had been produced which appears to indicate there is a potential investigation going on for our family.Ìý So, I’m pretty positive as to how things are going to develop for the younger generations of my family’s structure.

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White

So – but that’s the frustration, in a way, that even though you’ve both got this information, it’s not always given you, particularly perhaps in your case Martin, it hasn’t yet told you what you need to know.

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Hills

That’s correct Peter, but the one thing I would point out – I also had genetic counselling and the counsellor did actually warn me that that could easily happen.Ìý So, I was prepared for it which sort of deadened the blow a little bit.

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White

Let me bring Tina back.Ìý We’ve touched on some of the tricky implications – the things that you have to ask – there is genetic counselling available, as well as testing, just tell us about that.

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Houlihan

So, I think that it’s arguably as important to have counselling, as well as a genetic test.Ìý I think it all builds to the information that the family have about their condition, how that condition might progress, why they and their family may have been affected.Ìý As well as the precise diagnosis, counselling can offer all sorts of information on inheritance patterns, which I know both Martin and Bavini have touched upon, and provides really clear understanding of the risks to children, grandchildren and broader families.

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White

Now, we’ve not talked yet about things like restoring some sight or at least slowing down or even reversing deterioration.Ìý We feel we walk a bit of a tightrope on In Touch, you know, try to balance giving people good scientific information but not raising false hopes.Ìý But the fact is there is a lot of exciting work going on in this field involving things like gene replacement therapy and stem cell surgery but it’s necessarily slow.Ìý Only a few days ago we heard about a technique which claims to have restored some sight to a man in France with retinitis pigmentosa.Ìý The technique involves using a protein, which enables algae to swim towards light.Ìý It’s claimed that its use can restore light sensitivity to the eye.

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Well, our health and science correspondent, James Gallagher, reports.

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Gallagher

The man from Britany in France was diagnosed with retinitis pigmentosa 40 years ago.Ìý The condition leads to the death of light sensing rods and cones in the retina and in this case complete blindness.Ìý The researchers turned to optogenetics for a solution.Ìý It’s new to medicine but has long been a cornerstone of basic neuroscience.Ìý Essentially, it uses light to control the activity of individual nerve cells.Ìý It’s based on the proteins that microscopic algae use to swim towards the light.Ìý The instructions for these proteins were given to the surviving cells in the man’s retina and a special pair of goggles was used to convert natural light into the right wavelength to activate them.Ìý

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Dr José-Alain Sahel, from the Institute of Vision in Paris, said the patient first noticed a pedestrian crossing.

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Sahel

This patient initially – I think he was a bit frustrated because it took a long time between the injection and the time he started to see something.Ìý But when he started to report spontaneously that he was able to see the white stripes to come across the street, you can imagine that he was very excited.Ìý Everyone was excited.

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Gallagher

He can now grab and count objects on a table.Ìý This is far from perfect sight but the difference between no and limited vision can still be life changing.Ìý The researchers say their findings show the potential of optogenetics to restore sight and the same technology is also being investigated in conditions such as Parkinson’s and to see if it can aid recovery after a stroke.

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White

James Gallagher.

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Tina Houlihan, I imagine that this was news to you as well as to us.Ìý I mean what’s your reaction, not just to this but these kinds of stories?

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Houlihan

Well, first of all, Peter, I’d really like to thank you and the team for such a sensible approach to reporting what are very exciting progression in the scientific world but they have to be taken in a realistic view.Ìý So, it’s really exciting the optogenetics approach, this is the first in-human test, that means there’s a long way to go, there’s a lot more testing to be done.Ìý And this approach isn’t dependent on a genetic diagnosis.Ìý So, it’s very exciting stuff.Ìý But if I could manage that with a touch of sensibility and realism, there are a few things about this particular treatment that need to be taken into account.Ìý

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First of all, it restores vision to improve independent mobility, not vision as we understand it, so watching TV, lots of details and all that sort of thing.Ìý The other thing is that it was reported that it took several months after the treatment before this individual actually saw those first signs of vision.Ìý So, lots of really encouraging signs there but, as always, at Retina UK, we take that excitement and we look what it means realistically for the near future for the community.Ìý So, very exciting, things are going in the right direction but a certain amount of pragmatism needs to be used in terms of when this is going to be readily available and what the long-term efficacy on many people is.

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White

And Martin and Bavini, how do you react when you hear stories like this?Ìý Martin first.

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Hills

With caution.

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White

I think that’s all you need say really.Ìý Bavini, what about you?

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Macquana

Yeah, exactly the same.Ìý I think sometimes it gives a false sense of hope to a lot of people and it’s just how you manage those expectations afterwards.Ìý So, yeah, with caution is definitely the right word.

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White

Tina, what does the future hold for genetic testing in terms of visual impairment and where can it go and where are the best hopes do you think for future progress?

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Houlihan

Right, so, a few questions in there, Peter.Ìý So, firstly, I think that genetic testing is a very important part for this particular community because the conditions are genetically based.Ìý So, as well as all of the advantages and benefits to not only having the knowledge but going through the process, it’s really important, because in effect it’s a group of ultra-rare conditions bound by one set of symptoms, that we have as many people in the process and in the programme that might be available to participate in the increasing number of clinical trials and being able to access those treatments as they become available.Ìý So, it is exciting times, there has been a lot of breakthroughs in the last few years, most notably the Luxturna treatment, which was approved for NHS funding and the first patients have been through that process.Ìý And we, as an organisation and as a community, have learned so much about how to help that process.Ìý There’s very exciting progress in stem cells and, as you’ve read this week, in optogenetics but as we always say to the community, we keep them as fully informed as we can, so they can make decisions about their future and their families as both Bavini and Martin very efficiently said, with caution, hopeful caution.

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White

Right.Ìý Just one last quick question to Martin and Bavini.Ìý Martin, what would you say to people who are reluctant to seek testing?Ìý I mean some people feel they, in a way, they would rather kind of leave it in the lap of the gods and not take a risk and they point out that there are people who lead very happy and fulfilled lives when they’ve got retinitis pigmentosa and other congenital diseases.

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Hills

I think that’s a very important point.Ìý I think it’s horses for courses.Ìý There’s a certain degree of enthusiasm from some people and caution and maybe not wanting to know.Ìý And within a family structure that can vary as well.Ìý So, things have to be taken very sensitively, I think.

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White

Bavini, what about you?

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Macquana

Yeah, absolutely, I think people have the right to this service should they need it, should they want questions answering.Ìý For me, it definitely helped, I learnt all those questions about why me, why am I the only one, I got my answer.Ìý So, if people do want to know, it’s there, it’s available to them but just be cautious that you may get an inconclusive result, it’s not guaranteed.

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White

We’ll have to leave it there but thank you all – Bavini Macquana, Martin Hills and Tina Houlihan.Ìý We’d, of course, also welcome your response to this – would you be more likely to take a genetic test after what you’ve just heard?Ìý If not, why not?Ìý And if you already have, what changes for you as a result, what was different?

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You can email intouch@bbc.co.uk.Ìý Do go to our In Touch website where you can find this and many previous episodes of In Touch.Ìý And that’s it for this week.Ìý From me, Peter White, producer Simon Hoban and studio manager Mike Smith, goodbye.

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  • Tue 1 Jun 2021 20:40

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