It started with night blindness. After that, some of her visual acuity disappeared. Soon after, the point came that Ester found it irresponsible to get behind the wheel. “Until my thirtieth I could see perfectly, I remember what it is to have 100 percent vision. How much that is now is difficult to say.”
Good luck with technology
Ester sees best in daylight, but not clearly. “Pieces of field of vision are gone. But if I now look outside, at the forest, I feel like all the trees are ‘right’, because my brain fills up the empty pieces.”
With letters that is a different story. “I also only recognize people when they are standing in front of me, facing me. I am very lucky with technology; the camera on my phone is an extension of my eyes. When I try on new clothes, I see in a photo. better how it looks on me than in the mirror. “
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Ester’s disease is officially named retinitis pigmentosa type 17 (RP17). It is caused by a genetic defect on chromosome 17 (humans have a total of 46 chromosomes in each cell, 23 pairs).
Similar variant
This gene defect can make people visually impaired and even blind, a few years ago DNA research at the Radboudumc in Nijmegen showed. Then a specific region on chromosome 17 was designated where the gene defect should be located.
That hospital has been researching Ester’s family for 30 years into the cause of the visual impairment and blindness that affects a large part of the family. Worldwide, including in England and South Africa, there are about 300 people who have a similar variant of this gene defect.
Double sentence
But what exactly the gene defect is is only now known. Molecular geneticist Susanne Roosing, who is leading the research, explains how that works. “I compare a chromosome, in this case chromosome 17, to a page of words, where each gene is a word and has a function in the body (or a meaning in the sentence). In RP17, a sentence of that page is doubled. So not ‘the sky is blue’, but ‘the sky is blue the sky is blue’. “
One gene too many
Roosing and her co-researchers recently discovered that a person’s vision becomes worse because of the way that chromosome 17, with those doubles, is folded in the nucleus of a cell. “Normally that always happens in the same way, in neat DNA loops. But due to the DNA duplication, an excessively large DNA loop is created, with one gene too much in it. It is a breakthrough that this new mechanism has been found, which an ON button specifically turns on this extra piece of DNA in the retina. “
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And so the retina eventually produces a protein that a healthy retina does not produce. “The protein may be toxic to the retina,” says Roosing. “The normal function of that protein in the body is not yet known.”
That is why it is still difficult to say anything about a form of gene therapy that could remedy the defect. “We are working on follow-up research for this retinal disease, but that is not easy. However, this condition can occur when a child wants to have children, but they can then select embryos via an IVF process for the absence of the gene defect,” Roosing says.
Hope for a different future
That next generation is also something that Esther thinks about strongly. “I see this as the first part of a relay. The gene error has now been found. The next move is gene therapy and so we move on to a generation after me that does not have to suffer any more loss of sight. I would think that was the best. “
In the meantime, she does not give up herself. “I am very positive by nature. I miss a lot of vision, but I still enjoy every day what I can still do, because I know that it cannot be taken for granted. Because of this breakthrough, I have for the first time again hope that the future might be there. will look very different. “
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