Zebrafishes hope for the future?

If you suffer from the Usher Syndrome, your eyesight increasingly deteriorates.
This cannot be prevented yet, but perhaps this will be possible in the future. Last February, a campaign was started for the development of a possible treatment for people suffering from Usher type 2a.

For many years, I was in the belief that there was no treatment for the disorder that I and my daughter suffer from. I am hard of hearing, I have a small field of vision and I know that eventually I will become completely blind. I also know that my daughter will go through exactly the same process. Then I heard at a meeting that there might be some hope after all. This happened to Maartje de Kok, campaign leader of Ushersyndroom.nl. The campaign team collects money for the development of a genetic treatment method for people suffering from Usher Syndrome. This method may stop the deterioration of the eyesight. Here the team closely works together with the MUS Foundation, a foundation that supports people suffering from Usher Syndrome and their families.

Stop deterioration
Maartje and others draw hope from the Zebrafish project, a gene-therapeutic study into the development of a treatment for people suffering from Usher type 2a (Usher 2a). ‘There is no treatment at all for Usher 2a yet’, Erwin van Wijk explains. He is project leader of the Zebrafish project and researcher at the Radboud UMC. ‘Therefore we as yet specifically focus on this type of Usher. (HIER HOUDT HET ARTIKEL OP DE WEBSITE OP) Usher Syndrome is caused by mutations in genes. A gene contains the genetic code for the production of one or more proteins. In case of Usher this involves proteins that are crucial for the functioning of the eyes and the ears. We know by now that faults (also called “mutations”) causing Usher Syndrome can be found in ten different genes.
With this research we try to achieve that, despite this deviation in the genes, a protein is still produced that remains functioning sufficiently. In this way we hope to be able to stop the deterioration of the eyesight.’

In order to accomplish this, another method is used than the ‘classic’ gene replacement therapy that researchers in the United States use for Usher type 1b. ‘The therapy for Usher 1b does not work for Usher2a’, Erwin says. ‘This is because the gene to be replaced in case of Usher 2a is so large, that this is technically impossible. We try to solve this problem by applying an alternative approach, the so-called exon-skipping method. Here the “fault” in the gene is masked (“skipped”) so the body does not include this producing a new protein. The protein of such a repaired gene is not completely perfect. It is a bit shorter and therefore it does probably not function for 100%. However, we hope that it will function sufficiently to stop the deterioration of the eyesight. We want to test the effect of this method on zebrafishes. This is because the eyesight of zebrafishes deteriorates when the Usher 2a gene has a deviation, just like with humans. This contrary to mice, for example.’

‘The story of the Zebrafish project came to me as a bombshell’, Maartje remembers. ‘For three weeks, I was just busy asking myself whether I would dare to devote myself to making this research possible. After these three weeks I though that I just had to have the courage to do so. Even if this were not for me any more, then perhaps for my daughter.’

Fight against yourself
The Usher Syndrome has a great impact on the life of Maartje. ‘I have two physical impairments that negatively strengthen each other. This is not only highly inconvenient, it also costs a lot of energy. I also have four children. I impose limits on them in the house, but at the same time I want to be a fine mother.’ Therefore Maartje is constantly fighting against herself.
When she was told that daughter Jente also suffers from Usher, she saw her life pass before here eyes. ‘Problems with choosing a study, give up sports, no more riding a bike. She will also have to go through all those painful moments and I can only guide her if I can keep dealing with this in a proper way.’ This is hard, because sometimes being deafblind is frightening, Maartje knows. ‘I have experienced a moment that I did not hear and did not see anything. I had the flue and I felt the deafblindness come over me. I was terrified.’
‘At the same time, I can better let go of the disorder since I had this experience’, Maartje continues. ‘For I am still here. I run, I write blogs, I participate in the organisation of a large campaign. Even if I can see nothing in the future, then I am still here and there are lots of possibilities.’ Nowadays, she cuts up every day in pieces. ‘My family is my mindfulness training. I always focus on one thing. When I am walking the children to the bus, then this is what I am doing. I must not dream away or take my mobile phone while I walk.’

Maartje is a member of the campaign team that will make the Usher Syndrome widely known in the coming period. ‘We particularly want to make people aware, share knowledge and collect money with happenings’, according to Maartje. The MUS Foundation will organise a national Usher day on 12 September. This day is both for people suffering from the Usher Syndrome and for parents, guides and professionals. There will be lectures as well as workshops, personal accounts and music.

The team members will also participate in Co-cycling, a pleasure ride organised by interns on 20 June. ‘Here we will certainly attract attention with our tandems and buddies’, she thinks. ‘Our image is playful, frivolous, creative and certainly not miserable. We just hope we may keep our eyesight.’

In good spirits
How big is the change that the deterioration of the eyesight can be stopped indeed? Erwin emphasises that there is still a long way to go. ‘The first experiments are very promising, but we are careful. The last thing we want is to arouse false hopes in people.’ There are still a lot of questions. ‘Does it really work for humans? Is it safe, are there no side effects?’ A lot of money is needed to find answer to these types of questions.

Maartje: ‘110.000 euros for starting up the study and 90.000 euros for setting up the database. This database is necessary for being able to explain individual differences. Just to be perfectly clear, we collect money for all people suffering from Usher Syndrome. In fact, this study may also offer perspectives for other types of Usher.’
Maartje is in good spirits that the money required will be collected. ‘Also thanks to the partners a lot can be done. We already organise events ourselves and we also want to mobilise people. Perhaps this research will be too late for our generation, but then just let’s do it for the next generation.’

What is Usher Syndrome?
Usher Syndrome is a hereditary disorder that can visit both men and women. This syndrome was in 1935 called after the Scottish ophthalmologist Charles Usher, who did extensive research into this syndrome.
People suffering from Usher Syndrome are hard or hearing or deaf on both sides from birth.
Besides, they later develop a bad eyesight as a result of Retinitis Pigmentosa (RP), an eye disorder that affects the retina. The consequences of RP mostly reveal themselves in the teenage years, but in some cases earlier. Sometimes the functioning of the organ of balance is affected as well.

Usher Syndrome comes in three different varieties: types 1, 2 and 3. People with type 1 are born deaf or very hard of hearing and they have problems with their balance. Their eyesight deteriorates already at an early age. People with type 2 are born hard of hearing and their eyesight increasingly deteriorates in their puberty or in their young adultery. Usher type 2 is the most common type. With the rare type 3 the hearing of people increasingly deteriorates, but less is known about the further development of the disease. The number of people suffering from the Usher Syndrome in the Netherlands is estimated to be 600-1000.

Source: Oogmagazine nr. 2, mei 2015
Text: Jeroen Wapenaar & Joke van der Leij