Report CRUSH study

CRUSH: The natural history study

An interim report

The CRUSH study is a study done at the Radboud UMC into the natural development of progression with Usher Syndrome type 2a and USH2A-associated, non-syndromic retinitis pigmentosa (nsRP). CRUSH stands for Characterizing Rate of progression in USHer syndrome. This study is financed by Stichting Ushersyndroom and the co-financing of the Dutch Dr. Vaillantfonds and the Oogfonds.

Usher Syndrome and non-syndromic retinitis pigmentosa (nsRP)
With Usher Syndrome changes in the DNA (the hereditary material) affect the functioning of the cells in the ear and the retina of the eye, which leads to hardness of hearing and possibly balance problems and, additionally, deterioration of the eyesight in the course of time (retinitis pigmentosa). There are three types of Usher Syndrome of which Usher Syndrome type 2 is the most common type with over 50% of the cases. About 80% of the cases of Usher Syndrome type 2 involves type 2a, which is caused by mutations in the USH2A gene. Patients suffering from USH2A nsRP have the same kind of changes in the DNA, but they are not or less hard of hearing.

CRUSH study
This study examines the deterioration of the eyesight, balance and hearing of 40 patients suffering from Usher Syndrome type 2a and USH2A-associated nsRP. In view of the major individual differences in the level of deterioration of hearing and eyesight between people suffering from Usher Syndrome, we hope that the results of this study will provide more insight into the development of these disorders. Although there is no treatment yet at this moment, the results of this study will be indispensable for determining the effect of future treatments. 

Current state of affairs
The participants of the CRUSH study are annually tested. In a four-year period they are subjected to tests concerning hearing, eyesight and balance by means of various questionnaires. Because of COVID-19, we have had some trouble scheduling the second visits with respect to the study. By now, all measurements of the first two years have been done and, despite COVID 19, we are steadily proceeding towards the end.

People involved
Various people are involved in the study and we are pleased to introduce them to you: 

Dr. Ronald Pennings met een zwarte bril, een lach en hij draagt zijn witte doktersjas

Dr. Ronald Pennings

Dr Ronald Pennings, ENT specialist and head researcher
“My name is Ronald Pennings and as head researcher I am responsible for the CRUSH study, which means that I coordinate this study. This includes determining which people are subjected to which studies, adjusting protocols when a pandemic comes along, keeping an eye on finances, maintaining contact with the Usher Syndrome Foundation about the progress of the study and a lot of other things. The CRUSH study is really important, as with this study we can collect a lot more details about the deterioration of eyesight and hearing with people having mutations in the USH2A gene. These types of studies are essential for the preparation of future gene therapies. In short, with this study we are working together towards a treatment for Usher Syndrome.”

Erwin van Wijk in zijn lab en kijkt recht in de camera met een lach

Dr. Erwin van Wyk

Dr Erwin van Wijk, head researcher
“My name is Erwin van Wijk. As co-project leader I am involved in the set-up of the study and in selecting the participating patients who based on their genetic diagnose match well with the present developments in the area of gene therapies within my research group.”

Carel Hoyng kijkt serieus in de camera, hij draagt overhemd, colbert met een stropdas

Prof. dr. Carel Hoyng

Prof Dr Carel Hoyng: ophthalmologist and head researcher
“My name is Carel Hoyng, I am professor in ophthalmology and head of the Clinical Research Centre Ophthalmology. I am the head researcher of the ophthalmology part of the CRUSH study. I know most of the participants in the CRUSH study from my consultations. Unfortunately, I cannot often have a talk with the participants during their visits in connection with the study, but I know that Jack Weeda and the other researchers will take very good care of them. We surely have consultations about the participants on a regular basis. 

The CRUSH study is a very important study for us, particularly in view of future treatments and other developments. We expect that the next few years will be exciting years for ophthalmology and people suffering from hereditary retina disorders.”

Chris Lanting, kijkt met een open blik in de camera

Dr. Cris Lanting

Dr Cris Lanting, clinical physicist and audiologist
“My name is Cris Lanting and I am involved in the CRUSH study as a clinical physicist and audiologist. It is my job to support and supervise the audiological measurements and data analyses with respect to the various audio-vestibular results. Apart from this, I can give advice about the personal outcomes and revalidation options.”

Jack Weeda, draagt een bril en witte doktersjas

Jack Weeda

Jack Weeda, research optometrist
“My name is Jack Weeda and I started working at the Radboud UMC in the year 2006. I have worked as a research optometrist at the Clinical Research Centre Ophthalmology of professor Hoyng since the year 2012. In connection with the CRUSH study, all participants come to me for their screenings and follow-up visits. I examine the participants, for instance to determine their visual acuity and fields of vision and to make photos. Some participants recently came here for their third visits already and we start to know each other a bit. For me this is one of the nice aspects of this work, as contacts are more superficial at the clinic.

I hope that the results of the CRUSH study will make a contribution to gaining even more insight into Usher Syndrome and, of course, that we will soon be able to use them in treatment studies.”

Een vrolijk kijkende vrouw staat voor een muur met een kunstwerk en draagt haar verplegersjas

Addy Loeffen-van Dijk

Addy Loeffen-van Dijk, nurse
“Hi, my name is Addy Loeffen. I have worked at the ENT clinic as a nurse since May 2019. I temporarily take over the job of Lieke Knorth. This makes me responsible for various administrative tasks, but I also have direct contacts with our participants. I really like being able to add my share to this study.”

Een vrouw met blonde bos haren kijkt je recht aan in de camera

Patricia Gerrits-van Haren

Patricia Gerrits-van Haren, secretary
“My name is Patricia Gerrits van Haren, secretary patient care ENT. I have taken over the scheduling of the CRUSH study since mid-January of this year. I make sure that patients are invited and that all people involved are informed about this. In order to make this schedule run smoothly, I am in close contact with Jack Weeda, Addy Loeffen and Sybren Robijn.”

Een hele vrolijke blik van Sybren Robijn

Sybren Robijn

Sybren Robijn, research physician ENT
“My name is Sybren Robijn and I have as a doctoral candidate of Dr Pennings been involved in the CRUSH study since 2018. I have several tasks within the study. For example, I am responsible for various administrative matters, but I also often have direct contacts with our participants. In the course of the year, I will in full confidence pass on my tasks to my colleague Hedwig Velde. The thing that I will remember most from this study is the privilege of being given the chance to work with such highly motivated and zealous patients.”

Een vrolijke Hedwig Velde met haar in de staart en ze draagt een witte jas

Hedwig Velde

Hedwig Velde, research physician ENT
“My name is Hedwig Velde and I recently started as a doctoral candidate of Dr Pennings. I will take over the tasks of Sybren Robijn within the CRUSH study. I am looking forward to making a contribution to this link in the process towards a treatment for this patients group.”

Read also:
Patient and physician jointly take the first step towards treatment of deafblindness
CRUSH study and database for unraveling Usher Syndrome

The RUSH2a and the CRUSH studies


Nobel lecture CRISPR/Cas9 

with a digital tour of the fish lab

The Radboud PUC of Science has in cooperation with Radboudumc organised an on-line lecture about CRISPR/Cas9. This lecture was given on 10 December 2020the day that the Nobel prizes were presented. Researchers of the Ear Nose Throat (ENT) department of the Radboudumc explain the CRISPR/Cas9 technique in the light of their research into Usher Syndrome. 

The Nobel Prize in Chemistry was presented this year to the discoverers of the CRISPR/Cas9 technique, Emmanuelle Charpentier and Jennifer Doudna. The prize for the technique had been pending for some years already, because Crispr/Cas has been acknowledged as revolutionary examination technique for a long time already. And suddenly – poof! – we can change everything genetically, is how Doudna describes the importance of this technique. 

Previously, scientists always had to make genetic changes in organisms on the off-chance, for example by shooting at cells with radiation. However, Crispr/Cas works with an enzyme that searches the DNA for exactly the spot that scientists have indicated beforehand. This makes it possible to very precisely make changes in genetic material. 


Development of genetic treatment
Researchers Erwin van Wijk and Erik de Vrieze of the Ear Nose Throat (ENT) department of the Radboudumc explain the CRISPR/Cas9 technique in the light of their research into Usher Syndrome. 

Since the discovery of CRISPR/Cas9, they have applied this technology many times to make zebrafish models for Usher Syndrome, a rare hereditary disorder which causes people to be born hard of hearing and makes them slowly loose their eyesight as well. These genetically modified zebrafishes and the easy way in which they can be produced thanks to the discovery of Emmanuelle Charpentier and Jennifer Doudna, are the basis of the development of new genetic treatments for Usher Syndrome. 

Tour of the zebrafish lab
Following the lecture, both researchers will give a virtual tour of the zebrafish facility of the Faculty of Mathematics, Natural Sciences and Informatics, and show how the CRISPR/Cas9 technique is applied in practice. 

 The subtitling has been automatically generated and is therefore not always correct. 

Do you want to read more?
Research into Usher Syndrome on the Usher Syndrome Knowledge Portal
The research projects for which the Usher Syndrome Foundation collects donations and funds
In de Volkskrant, a Dutch daily paper: Nobelprijs scheikunde voor techniek waarmee we – poef! – opeens alles genetisch kunnen veranderen [Nobel Prize in Chemistry for the technique with which we – poof! – can suddenly genetically change everything]


Worldwide research study for patients with USH 1c

If you have Usher Syndrome Type 1C, your participation is critical to developing treatments. History studies are an essential part of bringing treatments to patients. As researchers get closer to developing therapies that will help slow, stop or reverse the degeneration of sight caused by Usher Syndrome, and specifically USH 1C, it is important to understand the history of progression of the disease in patients in order to confirm the effectiveness of those treatments.

There are 3 natural history studies that are ongoing for individuals with USH1C. The entry level study is open to all ages and does not require travel. Participation involves questionnaires and requesting medical records that can be done over the phone, via email, and/or video conferencing.
The other 2 studies – one for vision and one for balance – require travel to the US or Canada to see the doctors that specialize in Usher syndrome.

Usher 2020 Foundation are supporting therapies that include gene augmentation, drug therapies, and stem cell therapies. To move these treatments to clinical trials, they will need a thorough understanding of Usher Syndrome patients, and for some of these treatments, specifically USH 1C patients, the worldwide prevalence, and the clinical history of the disease.

Do you want to help and participate in this study? Then read the letters below and contact Dr. Jennifer Lentz.

Read more about the history study for USH 1c.
Read the letter here to participate.

Portret van oogarts Ingeborg van den Born

Is a treatment for USH 1B in sight?

story of ophthalmologist Dr. Ingeborg van den Born

Portret van oogarts Ingeborg van den Born

A natural development study for people diagnosed for Usher Syndrome type 1B was started already some time ago. This study is conducted in preparation to the clinical treatment trial (the project as a whole is called UshTher). How is this development study going and can on the basis of this study something be said already about the development of the disorder with people having mutations in the MYO7A gene? When will the UshTher clinical trial start and who will benefit from this gene therapy? Ingeborg van den Born, ophthalmologist and specialist in retina pigmentosa working in the Oogziekenhuis in Rotterdam, the Netherlands, tells about this and answers our questions. 

How can someone find out exactly which disorder he or she is suffering from and in which Usher gene the changes (mutations) are found? 
It is to be determined by means of an extensive examination of the eyes and ears whether (serious) loss of hearing and retinitis pigmentosa (retina degeneration – RP) are involved. A DNA test is required for making the correct diagnosis. As a matter of fact, more syndromes are known (although very rare) that also affect these two senses. 
For a DNA test a small vial of blood is taken and a special laboratory will examine this for changes that can explain the loss of hearing and eyesight. Sometimes a vial of blood from one of the parents is needed as well to see if the changes are coming from one parent or have been inherited from both parents.  

Why is it so important to have a DNA test done? 
Usher Syndrome is rare, which makes the chance of a child suffering from Usher very small. For each form of congenital loss of hearing it is advised to conduct a genetic test to find the cause of this. 

This test can confirm Usher Syndrome, even if there are no problems with the eyesight yet. Promising therapies are being developed, but in order to be eligible to these, it is necessary to know what is genetically going on. Therefore it is really important to have this examined. The first steps towards developing a gene therapy for USH 1B have been taken. 

Gene therapy development is complicated and costs a lot of time and money. For instance, it took many years to develop the gene therapy product Luxturna®, which can now be used in the USA and Europe to treat patients suffering from retinitis pigmentosa (RP) caused by mutations in the RPE65 gene (Leber congenital amaurosis) in an early stage. Here the healthy gene is surgically placed below the retina. We hope this medicine will be available for Dutch patients in a couple of months. Currently, gene therapy studies are running for other RP-genes as well, but not for genes causing a type of Usher Syndrome. 

What is gene therapy and do you have any experience with this? 
The objective of gene therapy is to cure a hereditary disease or to mitigate the complaints. There are various possibilities for this. For instance, a healthy gene can be added to the own DNA from outside. The healthy gene is inserted into the cell using a weakened virus, which is called a vector. 
The AAV virus is suitable for bringing DNA into the cell, but this can only contain small pieces of DNA. Professor Alberto Auricchio of the TIGEM Institute in Naples has worked for many years on a technique that can bring the MYO7A in two pieces into the cell and there put the pieces together again (double AAV vector). If this turns out to be successful, this may be really promising for a number of other genes. 

At this moment, this technique is further developed and if the results are fine, we hope it can also be tested on people in a phase 1-2 study. Presently, it is too early to tell whether this can already be done in 2021. 

In Florida, USA, Shannon Boy started a study into the development of a gene therapy for USH 1B using a double AAV vector with the help of a large subsidy from Fighting Blindness.
This study is needs testing on a large animal model before the therapy can be tested for effectiveness and safety in a trial on test persons.  

What are the differences between these two studies? 
I do not know the details of the study of Dr Sannon Boye, but the technique seems to be similar to that of Professor Auricchio. It is a good thing when several laboratories are focusing on the same disease and on the same technique, for this will eventually lead to a higher quality and probably accelerate the process. At this moment, it is impossible to predict whether both studies will eventually result in a properly working medicine. 

In 2019, a natural development study on people suffering from USH 1B was started in Naples, Madrid and the Oogziekenhuis in Rotterdam, the Netherlands. This study is done in preparation to the gene therapy trial. In this study the development and any deterioration of the eyesight is monitored for a period of two years by means of three detailed eye tests. The information gained from this study will eventually be very important to be able to compare the effect of gene therapy with ‘doing nothing’ over some period of time. Many patients yearly go to their ophthalmologists for a check and there they undergo a number of eye tests, such as a field of vision test. 

What are the differences between the natural development study and an annual check? 
A study visit often includes more tests than the annual check by your own ophthalmologist. For instance, in this study two types of field of vision tests are done instead of one and each year photos and a scan are made of the retina. Additionally, these tests are to be done following a fixed procedure, making the data gained from the tests conducted in Naples, Madrid and Rotterdam easy to compare. 

Have you been able to include sufficient patients in this study? 
In view of collecting proper data about the natural development of this type of RP, it was agreed to include 50 patients spread over the three countries. Usher 1B is a very rare disorder and therefore we are happy to have eight Dutch patients participating. Some of them will soon come for their third and last visits. 

It is still possible to participate in this study. Of course, this will take extra time and effort to go to the Oogziekenhuis in Rotterdam for a full day, but expenses and the like are compensated. The study includes a total of three study visits always with one year in between. 

Patients who want to participate in this natural development study can contact me (Dr Ingeborgh van den Born) or Ms Marja Scheeres (tel.: 010-4023437, e-mail: 

The Usher Syndrome Foundation wants to stimulate scientific research into the unravelling of and treatment for Usher Syndrome. Our mission is to have a treatment for Usher Syndrome in the year 2025. We want this for all patients, so for patients diagnosed for USH 1B as well. In the laboratory of the Radboud UMC research is mainly done into USH 1F, 2A and 2C and probably soon 1D as well. At this moment, no research is done into a treatment for USH 1B in the Netherlands. 

Can patients who are participating in the natural development study also participate in the UshTher clinical trial when this will be started? 
We have highly detailed information about the eyes of the people participating in the natural development study and we assume that some of them will be eligible to participation in the treatment study. Participation in treatment studies is often subject to strict criteria.  

Can Dutch patients who have not participated in the natural development study for USH 1B be eligible for participation in the UshTher clinical trial? 
This will probably be possible, provided that these people meet the inclusion criteria. 

Is the UshTher gene therapy promising for all patients suffering from USH 1B? 
The objective of gene therapy is to make the new, healthy gene improve the functioning of the affected retina cells and so slow down the process of the disease. This implies that this therapy can only work if there still is a minimum number of functioning retina cells. Consequently, patients who are blind and have no or hardly any functioning cells left, will not benefit from this type of therapy. 

Are there any hopeful developments for older patients suffering from USH 1B who have already lost many light-sensitive photoreceptors? 
As said above, unfortunately gene therapy will not help everyone and this means that research into other types of treatment, such as stem cells and, for instance, a light-sensitive chip is just as important.  

What do you think is the quickest and most effective path to a treatment for Dutch patients suffering from USH 1B? 
I think an important step has already been taken, being the cooperation from the Netherlands with the institute of Prof Auricchio. It is also very important that the Usher Syndrome Foundation itself also actively keeps in contact with him and the TIGEM institute. Eventually, it is all about cooperation between patients (associations), scientists and physicians.  

Additionally, we are working with rare disorders and therefore registration of patients is essential too. Besides, as you have also mentioned yourself, DNA tests are important to gain a good overview of the various mutations and genes of Dutch patients. By participating in the Ushther project we hope to make a contribution to the development of a treatment for Usher 1B.  

The Usher Syndrome Knowledge Portal provides additional background information about, among other things: 

Erwin van Wijk links in beeld, rechts naast hem een waterbak met kleine zwemmmende zebravisjes

The developments in the research laboratory

Erwin van Wijk links in beeld, rechts naast hem een waterbak met kleine zwemmmende zebravisjes

Despite the corona crisis, which has dominated our country for some time and as a result of which the research laboratory of Erwin van Wijk in the Radboud UMC for some time, quite some progression was made in the past year. Below you will find an overview of the most important achievements of last year. 

‘Genetic patches’ 

  • ProQR Therapeutics published the very promising intermediate results of the Stellar last April! In this Stellar trial the first group of people (with ‘faults in a specific part of the USH2A gene (exon13)) were treated on an experimental basis with the QR-421a molecule, the scientific basis of which was laid in the Radboud UMC. For this also take a look at ProQR publishes the first results of STELLAR’ or the website of ProQR Therapeutics, which Erwin and his colleagues closely cooperate with.
  • This year also saw significant progression in the development of ‘genetic patches for four other parts of the USH2A gene. More information will be provided about this in the course of the year 2021. 
  • We set up the Dutch Center for RNA Therapeutics together with the LUMC. In this centre we will develop genetic patches for covering extremely rare hereditary faults. Extremely rare means that they occur only once or twice in the whole world. The development of the layout and the set-up of the centre portal is still in full swing. Here you can read additional information about the foundation of the DCRT: A genetic patch for very rare mutations. An update will follow in the course of this year.  
  • In cooperation with the research group of Dr Monte Westerfield and Dr Jennifer Phillips (University of Oregon, USA) and the USH1f Collaborative, we expanded the genetic patch methodology to the PCDH15 gene (= Usher syndrome type 1F). 

Minigene therapy 

  • The development of a minigene therapy for Usher syndrome type 2C was started in April 2020. This is a four-year PhD project financed with contributions from the Usher Syndrome Foundation, LSBS and CureUsher. A part of this project also included further optimisation of USH2A minigenes

Study into quality of life: Sleep study 

  • Apart from their visual impairment, many people suffering from hereditary poor eyesight and Usher Syndrome also have sleeping problems, possibly as a result of a deviating day-night rhythm. These problems have a great impact on the well-being of patients suffering from hereditary blindness, but they are hardly recognised as a part of the disorder. We wrote a four-year research proposal aimed at gaining a better understanding of this problem, making the scientific world, care professionals and health insurance companies recognise this and, finally, solving this by having it included as a part of the current care paths. After assessment by a scientific committee, the project ended up in the top 3 of best projects! About two thirds of the required funds have been assigned by ANVVB, LSBS, Stichting Beheer het Schild, the Gelderse Blindenstichting en the Usher Syndrome Foundation. At this moment we are raising the remaining part of the required funding so that we can actually start this important study by mid-June 2021! Read more about ‘Recognition of sleeping problems with patients’. 


Documentary Silence in the night

Would you rather be deaf or blind? Joyce de Ruiter (36) from the Netherlands can’t choose, she eventually will be deaf and blind because of Usher syndrome. Her path to acceptance was accompanied by three burn-outs, but now she uses the diagnosis as her strength, she gives lectures and is a source of inspiration for many.
In the Campusdoc documentary Silence in the night (Dutch: Stilte in de nacht) we follow her path to acceptance and show the viewer how she deals with the fact that she is a source of inspiration for many.

Usher syndrome
Usher syndrome is a rare genetic disorder in which children are born deaf or hard of hearing and experience a progressive loss of sight in addition to night blindness. Sometimes there are also balance problems. In the end, people with Usher syndrome become deaf and blind.

About the makers and Campusdoc
Milou op ten Berg and Lisanne van Spronsen are the makers of this documentary. They are both third-year students at the School of Journalism in Utrecht. Through Lisanne’s mother she heard Joyce’s story and felt that more recognition should come for Joyce, but also for the syndrome.

They decided to sign up together for the Campusdoc, a special minor in which a total of twenty students will make ten documentaries, which (if covid-19 permits) will premiere in the Louis Hartlooper Complex in Utrecht in the week of 18 January. During the film festival, a professional jury will decide who wins the jury prize. After this, the documentary will be screened at other international film festivals.

To make this film a reality the filmmakers need some money. This way we can make the documentary as special as Joyce her story is. Fifteen percent of the entire proceeds they donate to Stichting Ushersyndroom, so that they in turn can have research carried out into a treatment. Their target amount (7,000 euros) has almost been reached, but with even more money they can also have the film premiered (corona proof) and more money will automatically go to Stichting Ushersyndroom. You can make a donation here Cinecrowd/Stilte in de nacht. 


Do you want to follow the process of this documentary?
website ‘Stilte in de Nacht’ 
Instagram @stilteindenacht
Facebook @stilteindenacht

Cinecrowd/Stilte in de nacht.


HURRAY! Everything you want to know about Usher Syndrome has now been put together!

Stichting Ushersyndroom launches the Usher Syndrome knowledge portal. 

Today, a long-cherished dream of many families confronted with Usher Syndrome will come true. So far, information and knowledge about Usher Syndrome were hard to find and highly fragmented. The Usher Syndrome knowledge portal is made available by the Stichting Ushersyndroom and it will be officially launched by Dr. Ronald Pennings of the Radboudumc in Nijmegen, the Netherlands, with a festive touch. 

Stichting Ushersyndroom (formerly Stichting MUS) was established in the year 2012 from a need to share experiences and information with each other. When being diagnosed for Usher Syndrome, you have the ‘sword of Damocles’ hanging above your head and you will have a lot of questions, such as: ‘How can I live my life knowing that my child will become both deaf and blind?’
Today, Stichting Ushersyndroom will launch a portal that has been developed for and by people suffering from Usher Syndrome in which they as Usher experts by experience have put together all their knowledge and information. If you want to help us further develop the knowledge portal, please contact us through

Festive touch
Ronald Pennings, MD, PhD, ENT consultant and Usher syndrome specialist of the Radboudumc in Nijmegen, will virtually open this portal with a festive touch.


Renewed campaign site
Simultaneously with the development of the knowledge portal, Stichting Ushersyndroom also gave the campaign site a new look. You can easily switch between the campaign site and the knowledge portal using the footer at the bottom of each page of the website.

Sharing knowledge and information is essential for unravelling Usher Syndrome. Usher Syndrome is a serious hereditary disorder that has a far-reaching impact on the lives of people suffering from Usher Syndrome and their social environments. We wish to eliminate this disorder from the bottom of our hearts. Therefore Stichting Ushersyndroom has formulated the following mission: ‘A treatment for Usher Syndrome in 2025!’

Support us and make our dream come true!


ProQR announces first results from STELLAR

Summary of Phase 1/2 Interim Analysis of QR-421a for Usher Syndrome Program

A first-in-human clinical trial of QR-421a is ongoing. The Phase 1/2 study, named Stellar, includes adults that experience vision loss due to mutation(s) in exon 13 of the USH2A gene. This Phase 1/2 clinical trial is designed to evaluate the safety and tolerability of QR-421a. Patient benefit will be assessed as well.

Three-months interim findings from Stellar, reported in March 2020, suggested QR-421a given as a single intravitreal injection was safe and well tolerated. QR-421a showed early and encouraging evidence of activity, with 25% of patients showing a benefit across multiple concordant outcome measures and was well tolerated with no serious adverse events. Two of eight participants in the treated groups responded to QR-421a treatment thus far showing benefit in multiple outcome measures.

Across both cohorts thus far, QR-421a was observed to be generally well tolerated with no serious adverse events noted. Based on these early positive findings we will continue the trial as designed at expert centers in North America and select European countries.

Read here the PDF:  Interim Findings of QR-421a Phase 1/2 Clinical Trial for Usher Syndrome and nsRP 

Read press release: ProQR Announces Positive Findings From an Interim Analysis in the Phase 1/2 trial of QR-421a for Usher Syndrome and Provides Business Update



A tailor-made genetic patch for very rare mutations

New centre for RNA therapy set up for small patient groups.

Scientists and physicians of the Leiden University Medical Centre (LUMC) and the Radboudumc together started the Dutch Center for RNA Therapeutics (DCRT). This new virtual centre was set up with the objective to develop tailor-made RNA therapy. A therapy meant for patients with rare genetic disorders, such as Usher Syndrome.

Dutch Center for RNA Therapeutics
The DCRT opened its doors for the first time on 29 February 2020, Rare Disease Day. The DCRT is the first centre in Europe to develop RNA therapy for very rare diseases. This is about genetic diseases and mutations that are so rare, that it is less interesting for pharmaceutical companies to invest in developing a treatment. The therapies are targeted on stopping or slowing down progressive genetic eye, brain and muscle diseases by local administration of medication.

RNA therapy for Usher Syndrome
The objective of RNA therapy, also called AON therapy, is to repair the genetic defect at RNA level, so that a smaller but partly functional Usher protein can be made.
For a specific mutation an antisense oligonucleotide can be designed. Antisense-oligonucleotides, abbreviated by ASOs or AONs, can be regarded as a ‘genetic patch’ that covers the area of the mutation and makes it invisible. In this way the cause of Usher Syndrome is removed and, hopefully, the deterioration of the eyesight (and possibly hearing) with this group of patients can be stopped or mitigated.
Erwin van Wijk of the Radboud UMC in Nijmegen, the Netherlands, studies the therapeutic effect of antisense oligonucleotides (AON) for the future treatment for Usher Syndrome.
Jennifer Lentz from New Orleans (LSU School of Medicine, USA) is working on the development of an antisense oligonucleotide (AON) for patients with a specific mutation in the USH1C gene, the c.216G>A mutation.

Over 500 different mutations are known for the USH2A gene and RNA therapy is not possible for all these mutations. RMA therapy will be possible for about one third of the people with mutations in the USH2A gene, but some mutations are extremely rare. The new Dutch Center for RNA Therapeutics (DCRT) wants to develop tailor-made ‘genetic patches’ for this really small group of patients.

‘It is impossible for the industry to make medicines for only a few patients. Therefore it is the duty of the academic hospitals to be there especially for that group’, according to scientist Anniemiek Aartsma-Rus.

The in-house making of a ‘genetic patch’ for one specific mutation has one factor that saves a lot of time. No registration with the European Medicines Agency (EMA) is required.
Together with patients’ associations and subsidies this centre must be developed further in order to make sure that an (affordable) ‘genetic patch’ will be available for all patients with (very) rare mutations in the Usher gene in the future.

The DCRT is made possible by a financial contribution of the Human Genetics department of the LUMC. This non-profit centre will be managed by Dr. Willeke van Roon-Mom and Prof. Annemieke Aartsma-Rus of the Human Genetics department of the LUMC Also neurologists Dr. Erik Niks and Prof. Jan Verschuuren, ophthalmologists Prof. Camiel Boon and Prof. Gré Luyten and hospital pharmacist/clinical pharmacologist Prof. Henk-Jan Guchelaar are involved in this as well. Apart from Dr. Collin, geneticists Prof. Frans Cremers, Dr. Susanne Roosing and Dr. Alex Garanto as well as Dr. Erwin van Wijk as researcher of the ENT department, ophthalmologist Prof. Carel Hoyng and ENT specialist Dr. Ronald Pennings from Nijmegen are involved in the DCRT as well.

Read here more about Dutch Center for RNA Therapeutics

ProQR Therapeutics from Leiden has further developed the antisense oligonucleotides (AON), developed by Dr. Erwin van Wijk, into the medicine QR 421a and this is currently tested for effectiveness and safety in a trial called STELLAR. This is a ‘genetic patch’ for exon13, the most frequently occurring mutation in the USH2A gene. The first results will soon be published.
The ‘genetic patch’ must be regarded as a medicine and not as a gene (replacement) therapy. This is because actually no gene is replaced or repaired. The ‘patch’ must be administered repeatedly in order to have a permanent effect on the deterioration of the eyesight.

Development of gene therapy for large USH2C gene

From left to right: Annouk van Nunen, Rick Brouwer, Deborah Heffernan, Erik de Vrieze, Erwin van Wijk, Ronald Pennings, Carol Brill, Renske Schellens, Ivonne Bressers, Sanne Broekman, Jantine van de Watering.

Usher Syndrome patients and researchers of Radboudumc set the tandem in motion again for scientific research into a treatment for Usher Syndrome, this time concerning type 2C. After the successful USH2A Minigenes study, the results of which will be known early in the year 2020 there will be a follow-up. Stichting Ushersyndroom (Dutch Usher Syndrome Foundation) finances, with a contribution from CUREUsher from the UK/Ireland and the Landelijke Stichting voor Blinden en Slechtzienden (LSBS), the new study into Minigenes for USH2C. In order to celebrate this milestone, five researchers of the national Usher Syndrome Expertise Centre of the Radboudumc involved surprised the same number of patients with a ride on the tandem. 

In their white coats head researcher Erwin van Wijk, Erik de Vrieze and ENT specialist Ronald Pennings cycled in a good humour as co-pilots to the agreed place. Only Ivonne Bressers, chairwoman of Stichting Ushersyndroom (Usher Syndrome Foundation) was involved in the plot. Like a string another two half-empty tandems followed with 2 young researchers who are daily engaged in doing research into a treatment for Usher Syndrome, a disorder which slowly makes 400,000 patients around the world both deaf and blind.

With rare diseases like this, the contact between physicians, researchers and patients is crucial. Patients, parents and relatives are the drive force behind the scientific research into a treatment by collecting donations, acquiring resources and close consultation with physicians and researchers. This interaction brings a treatment for progressive deafblindness closer at a faster pace.

“We are unmistakably united as a duo on a tandem; the researcher as co-pilot, the patient as firer.”
Erwin van Wijk, head researcher in the Radboudumc

“The input and knowledge that patients bring up themselves is not only highly inspiring for me and my colleagues, these also put us on new tracks in unravelling Usher Syndrome. We are unmistakably united as a duo on a tandem; the researcher as co-pilot, the patient as firer,” the head researcher of Radboudumc Erwin van Wijk tells us.

Five Usher patients are sitting at a table in a café drinking coffee; some with their backs to the window. Patient Rick Brouwer gets up surprised when Erwin van Wijk appears within his tunnel vision. Rick is one of the people for whom the Minigenes USH2C study gives hope. He has been involved as from the foundation of Stichting Ushersyndroom (Usher Syndrome Foundation) and suffers from Usher Syndrome type 2C himself.
“Today really is an important day! Thanks to the positive results of the Minigenes USH2A study a step is made to USH2C. There soon will be a treatment for all people suffering from Usher!”, Rick calls out deliriously happy.

“For the first time in my life I really have hope that there will be a treatment for all Usher patients all over the world!”
Carol Brill, Usher patient and member of the Board of CUREUsher

Carol Brill of CUREUsher from Ireland is there as well and starts laughing when the researchers seduce them to take a ride on the tandem after having expressed their thanks for their cooperation. Carol: “What a great experience to cycle together through the city! I will come over to live here! For the first time in my life I really have hope that there will be a treatment for all Usher patients all over the world!”

Promising preliminary investigation
In the year 2016, Stichting Ushersyndroom (Usher Syndrome Foundation) made a financial contribution to the study into the functioning of USH2A Minigenes as a future treatment method. Usher Syndrome is a rare genetic disease in which faults (= mutations) in about ten different genes lead to a progressive form of deafblindness. The large size of the genes in which the most causal mutations are found with most patients makes classic gene therapy impossible. This is because these mutated genes are simply too big to be packed in the available viral vectors that are required for delivering the gene at the correct place in the retina. This is an ultimate challenge for the researchers. A creative solution is needed to still process the gene in a viral vector.

Erwin van Wijk expects to be able to publish the first study results of the USH2A Minigenes study early in the year 2020. Van Wijk will now start a similar study for USH2C, titled ’Pre-clinical development of a minigene augmentation therapy for the future treatment of USH2C-associated retinitis pigmentosa’. Never before a research institute has had the courage to start developing a gene therapy for this huge USH2C gene. Stichting Ushersyndroom (Usher Syndrome Foundation) will subsidise this 4-year study of Erwin van Wijk (and Erik de Vrieze and Ronald Pennings) with € 250,000 with co-financing from CUREUsher and L.S.B.S.

In order to celebrate this milestone, five researchers of the national Usher Syndrome Expertise Centre of the Radboudumc involved surprised the same number of patients with a ride on the tandem. 

The Medical Advisory Council of Stichting Ushersyndroom (Usher Syndrome Foundation) is very positive about this study because of the highly promising preliminary investigation with the USH2A Minigenes, which has demonstrated that it is possible to make minigenes and that these work in the correct/expected way.

According to the members of the Medical Advisory Council, the applicants have the appropriate knowledge, expertise and material at their disposal to carry out the proposed experiments for the USH2C gene (ADGRV1). As far as the members of the Medical Advisory Council know, no study is presently done into USH2C, while this is the third most common form of Usher Syndrome which about 40,000 people around the globe are suffering from.
Cindy Boer (member of the Medical Advisory Council, doctoral candidate internal medicine, faculty of human genomics, ErasmusMC and suffering from Usher Syndrome herself): “In consultation with Erwin van Wijk and Erik de Vrieze the Medical Advisory Council has made an addition to this study proposal. We would like to apply this to humans by making use of human skin cells. In this way we can investigate whether the minigenes behave well in human cells and whether the proteins properly unfold. This may sometimes be different in human models as it is in animal models and therefore it gives a good indication about the functioning of the gene therapy for humans.”
The USH2C Minigenes study is completely in line with the objective of Stichting Ushersyndroom (Usher Syndrome Foundation): “There will be a treatment for Usher Syndrome in 2025!”

The tandems with patients and researchers will continue their journeys; these will be bumpy, but their confidence in the process will drive them and this will bring a treatment for Usher Syndrome closer than ever before. Difficult ways will lead to great destinations. 

The CRUSH study as a preparation for future trials
Earlier this year, Stichting Ushersyndroom (Usher Syndrome Foundation) also financed the CRUSH study of the Radboudumc with co-financing from the Oogfonds and the Dr. Vaillantfonds, a study in which researchers will map out the natural development of Usher Syndrome in great detail. Researchers really intensively follow the Usher Syndrome patients. Expectations are that during a research period of five years more knowledge will have been gained about the development of the deafblindness related to various types of Usher Syndrome.
In case of a positive result of the new study into Minigenes for USH2C the research team will be well prepared for any next phase 1 / 2 clinical trial.

Text: Maartje de Kok
Photo and video: Richard Brusse

Read also:
How are things going with the ‘minigenes USH2c’ study?