There needs to be more awareness about genetic sight loss among the public and specialists, an expert has said.
Inherited sight loss conditions are the most common cause of blindness in working age adults in the UK.
While there is a lack of accurate data on the number of people affected by these conditions, estimates vary between 21,000 and 35,000.
A condition called retinitis pigmentosa is the most common cause of inherited sight loss – and it is thought at least 10,000 people and possibly as many as 17,000 have it.
It can see people struggle with their vision in low light, lose peripheral vision, and eventually lose their sight.
While there is currently no cure for inherited sight loss conditions, there is increasing work in the development of treatments – driven by advancements in genomic science.
Experts suggest the key to additional progress lies in more people having genetic tests.
Dr Mariya Moosajee, consultant ophthalmologist at Moorfields Eye Hospital, told the PA news agency: “Once you have an individual that you identify to have a genetic eye condition, it’s really important to think about what to do next, both as the patient but also as a doctor that’s picking this up.
“The NHS now has a genomic medicine service, which means that any patient with a genetic disease can access something called whole genome sequencing.
“That is the highest and best form of genetic testing.”
This testing allows experts to look at an individual’s whole genetic code – which is three billion letters in size and contains 20,000 genes, and allows them to come to a potential genetic diagnosis.
This means patients can be told the cause of their condition, which gene is not working properly, and what the mutation is.
Dr Moosajee added: “But not everyone knows that they can access that. And not all doctors know that they can refer patients for this.
“And so that is key that we spread that awareness that this service is available to these rare disease populations.
“And then once you’ve made that genetic diagnosis, that will inform the information, the management, that we provide those individuals.”
She continued: “And so I would just urge everyone that has a genetic-based condition to come forward to search out the doctors and the specialist centres around the UK that can provide genetic testing so that we can find out their cause.
“And then we can start to begin to have conversations about whether or not there is a treatment available for them.
“Or if there is a clinical trial that they may want to enter into that could potentially help them.
“We need to raise awareness amongst optometrists, high street opticians, GPs, they need to know that if this is picked up that they can refer these patients into our specialist services.”
Now a 20-year-old student at the University of Oxford, Sol Woodroffe, from Bristol, had no idea anything was wrong until he was around 11 years old and his father noticed him being clumsy and took him to an optician.
His diagnosis of retinitis pigmentosa was determined by looking at images of the back of his eyes aged 12, and in 2016 he was invited to join Genomics England’s 100,000 Genomes Project to have his whole genome sequenced to see if a genetic cause could be identified.
Unfortunately the gene that causes the condition for him could not be pinpointed, but he is hopeful he might get the answers one day, and keeps on top of developments in the field.
Mr Woodroffe told PA: “It just makes you feel like you have a little bit more autonomy over your own condition, because I think sometimes people can feel a little bit like they’re at the whim of a consultant or a doctor.
“If we can just centralise all that information and get it into one place and let anybody who’s got access to the internet see it, I think it’s great.”
Mr Woodroffe explained that his mother had been tested in order to see if there is a genetic link from her side, but one was not found.
He continued: “I think it’s really important to get people with rare genetic diseases to talk about them and encourage people to get tested.
“I think there’s a real wave, and all this stuff about people getting their DNA tested for their ancestry.
“But I think it would be great if we could turn that into people getting their DNA tested for medical purposes and allowing that information to be accumulated.
“People are very sceptical about it and can be borderline conspiratorial about sharing their genome and things.
“But I think it’s a real shame because I have a lot of faith and trust in Genomics England and what they’re doing.
“They have very good evidence that they’ve made lots of fantastic progress and just improved the quality of people’s lives.”
Bhavini Makwana received a diagnosis of retinitis pigmentosa when she was 17 and for many years hid her condition.
Now, 25 years on she has no vision in one eye, very little in the other and uses a guide dog.
“I think research is important because if not in my lifetime, then it would help the next generation,” she said.
She added that it was important for people to be aware of genetic conditions, saying that until she got her diagnosis some in her community had suggested it was karma that she was losing her sight.
Mrs Makwana told PA: “Forgetting that side of it, it helped me understand. Because I remember the diagnosis was literally that this is what you’ve got.
“There’s nothing they can do. And this is how long it could take to deteriorate because everyone’s different. And I think I struggled with that for so many years because I didn’t know what that meant.”
Tina Garvey, chief executive of charity Retina UK, said: “Far too many people living with inherited retinal dystrophies (IRDs) are still unaware that genetic testing and counselling is available to them for free through the NHS.
“Being diagnosed with an inherited sight loss condition often means there is a great deal of uncertainty ahead but, with access to the right information, there are some areas that people can make informed decisions about and have some control over.”
Dr Richard Scott, chief medical officer and deputy chief executive at Genomics England, said: “Knowing the genetic cause of an inherited disease like retinitis pigmentosa is empowering, both for the individual and their family.
“A decade on from the launch of the 100,000 Genomes Project, we’re continuing to work in partnership with the NHS to harness the potential of genomic medicine, connecting research and clinical care at a national scale so we can deliver benefits in diagnosis, treatment, and care for those living with rare conditions.”