About LCA

What is Leber’s Congenital Amaurosis?
Leber’s congenital amaurosis (LCA) is the most common genetic cause of childhood blindness and affects about 15,000 patients in the Western world. LCA leads to poor vision and blindness for which there is currently no approved treatment. The disease usually appears in the first year of life and is characterized by progressive loss of vision. In some cases, patients eventually become severely visually impaired and depending on the mutation, complete loss of vision will occur during early childhood.

In LCA a process called photo transduction is disrupted in the light detecting cells (rods and cones) in the retina, due to a mutation in a specific gene. Because these cells cannot perform their function properly patients experience nystagmus (involuntary eye movement) and severely impaired visual function.
What causes Leber’s Congenital Amaurosis?
LCA is caused by mutations (or defects) in certain genes present in the DNA. There are over 19 known genes that can cause LCA when they are mutated. The most prevalent mutation is the p.Cys998X mutation, also known as c.2991+1655A>G mutation in the CEP290 gene causing Leber's congenital amaurosis 10 (LCA 10). The CEP290 gene is responsible for expression of the CEP290 protein (centrosome- and cilium-associated gene centrosomal protein 290). LCA 10 accounts for the most severe form of LCA. Although diagnosis rates vary, we believe approximately 2,000 patients in the Western world have LCA 10 due to this mutation.

Amongst other functions, the CEP290 protein helps the development and maintenance of cilia in the photoreceptor cells (rods and cones) in the retina. A non-functioning CEP290 protein causes subsequent retinal degeneration in LCA 10 patients.
There are currently no approved treatments that treat the underlying cause of LCA 10.

About QR-110

ProQR is developing a novel drug, QR-110, for Leber’s congenital amaurosis 10 patients that suffer from the p.Cys998X mutation, also known as c.2991+1655A>G mutation, in the CEP290 gene.

QR-110 is designed to work in a unique way. It aims to repair the genetic defect in the RNA, such that it leads to a normal “wild-type” mRNA. The RNA is the "blueprint" for protein synthesis. By repairing this "blueprint" a normal healthy CEP290 protein will be formed that is expected to have normal function. The goal of QR-110 is to repair the underlying defect in the RNA and potentially stop the progression of the disease or reverse some effects of LCA 10 caused by the p.Cys998X mutation. QR-110 has received orphan drug designation from the U.S. Food and Drug Administration and European Medicines Agency. QR-110 was also granted fast track designation by the U.S. Food and Drug Administration.
Clinical trials
In 2017 we started our first clinical trial for QR-110. In the phase 1/2 trial approximately six adults and six children that have LCA 10 due to the p.Cys998X mutation in the CEP290 gene will participate. The trial is planned to be conducted at three academic hospitals in the USA and Europe.

This phase 1/2 clinical trial is necessary to evaluate the safety and tolerability of QR-110. Patient benefit will be assessed as well.

Information for patients

QR-110 is an experimental medicine that we are developing for LCA 10 patients with the p.Cys998X mutation in the CEP290 gene (also known as c.2991+1655A>G mutation). We have moved the program through the early stages of the development and started the first clinical trial in people. For more information about the program please visit this page or the page about the clinical trial where we will post regular updates. If you have any other questions please read the FAQ below or contact us through the contact form and we will be happy to answer any question you have.


Who is ProQR?
ProQR Therapeutics is a European company, founded in 2012 to develop a life changing therapy for patients suffering from severe genetic disorders like cystic fibrosis, Leber’s congenital amaurosis (LCA) and dystrophic epidermolysis bullosa (DEB).
What is QR-110?
QR-110 is an experimental medicine that is designed to treat LCA 10 patients with the p.Cys998X mutation in the CEP290 gene. QR-110 aims to restore a normal mRNA in patients resulting in normal CEP290 protein with the goal of stopping the progression or reversing the effects of the disease. QR-110 has shown promising results in the lab and the clinical trial for human testing is ongoing.
When and where will QR-110 be tested?
ProQR has started the first clinical trial in 2017 at academic hospitals in the US and Europe. Updates will be posted to this website so please check back regularly.
Can I participate in the trial?
The QR-110 study is planned to be conducted in three academic hospital centers in the US and Europe with significant expertise and collectively managing enough LCA 10 patients to fully enroll this small trial with 12 patients (6 adults and 6 children age 6-17). Therefore, the opportunity for participation in this trial will likely be limited. We suggest that you talk with your treating physician to discuss your options and if you have additional questions on the study to ask your physician to contact the trial site closest to you.
I have a LCA CEP290 mutation other than p.Cys998X, is QR-110 developed for me?
QR-110 is specifically designed to target the p.Cys998X mutation and is not expected to work in other mutations.
How often will QR-110 be given?
We expect that QR-110 will be a chronic treatment, meaning that patients will need to receive QR-110 on a regular basis. More information on the dosage and frequency of treatment will be gathered after the first clinical trial.

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