The RUSH2a and the CRUSH studies

CRUSH has been aligned to RUSH2a
Also thanks to the Medical Advisory Council of the Usher Syndrome Foundation, the content of the CRUSH study has been aligned to RUSH2A. This means that the research questions and the study measurements are largely similar, allowing the results of the CRUSH study to be compared with those of the RUSH2a study. This comparison is of scientific value.
The set-up of the CRUSH study leaves the expertise centre in Radboud UMC some space to make adjustments in the research protocol. In the international RUSH2a study this is highly restricted, as this study is to be conducted in all countries in exactly the same way.
Examples of differences are: the CRUSH study is somewhat more focused on the quality of life (questionnaires). The CRUSH does not apply a smelling test, but the RUSH2a study does. The CRUSH tests for balance, which the RUSH2A does not. The RUSH2A applies genetically stricter inclusion criteria. Some patients are not eligible for RUSH2A whereas they are for CRUSH and vice versa.

A large group of patients
Internationally, both syndromic and non-syndromic Usher patients are eligible for the RUSH2a study. Patient will not participate in both studies.
Patients with non-syndromic retinitis pigmentosa are not eligible for the CRUSH study.
Only patients with a mutation in the 2a gene will participate in the RUSH2a studies. The CRUSH study can include patients with mutations in various gene types. Both studies are equally important from a scientific point of view. One study does not have more advantages or risks than the other.
20 patients can participate in the RUSH2a study and for the CRUSH study 50 patients will be selected and asked to participate. The RUSH2a will be coordinated from the Ophthalmology department department, whereas the ENT department coordinates the CRUSH study.

What about the database?
The CRUSH database is a database specifically set up for patients suffering from Usher Syndrome. Here not only the contact data and genetic results are saved, but those of the field of vision and hearing tests as well. The CRUSH database provides an overview of all patients suffering from Usher Syndrome in a uniform database and this may simplify selection processes for participation in a study and/or trial.
The CRUSH database is managed by the Usher Syndrome Expertise Centre in the Hearing & Genes department of Radboud UMC.
An Usher Syndrome patient who has been registered for the RD5000 database will not automatically been registered for the CRUSH database and vice versa. The ENT specialists and the ophthalmologists in Radboud UMC work closely together, thus ensuring exchange of knowledge within this Academic Centre. You can register for the CRUSH database by sending an e-mail to

Natural development for USH 1B
A study into the natural development with patients suffering from the Usher Syndrome type 1B was started in the Oogziekenhuis Rotterdam, the Netherlands. The information gained from this study will eventually be very important to be able to compare the effect of gene therapy.