Gene name: WHRN (also known as: CIP98, DFNB31, PDZD7B, USH2D)
Gene size: 4070 (bp)
Protein name: Whirlin
Protein size: 907 (aa)
There are 9 different transcripts known for this gene
There are currently a number of trials that may be relevant to patients with mutations in the USH2D-gene:
- Stem cell therapy jCyte
- Stem cell therapy Cedars-Sinai
- Natural history study CRUSH
- Medicine SLO-RP
In Australia, a clinical trial phase 1/2 was started with financial support from the Foundation Fighting Blindness.
Nacuity Pharmaceuticals launched this trial under the name SLO-RP. The safety and effectiveness of the medicine NPI-001, an experimental antioxidant, will be tested in the coming two years. The medicine appears to be really promising for slowing down the deterioration of eyesight with people suffering from RP and Usher Syndrome, irrespective of which gene is defective or which mutations have taken place.
In a study of the group of Wade Chien (NIDCD, Bethesda, USA) a healthy copy of the whirlin gene was delivered using an AAV vector to the inner ear of new-born mouse models of which the whirlin gene had been disabled.
jCyte, is a company that has developed retinal progenitor cells (RPCs), a type of stem cell that only retinal cells can become. Clinical studies have shown that these cells can reach and even replace diseased retinal cells. The results of a phase 1 / 2a trial have shown that the treatment is safe and does not cause an immune response.
The Los Angeles-based Cedars-Sinai company has also received approval from the FDA to initiate a phase 1 / 2a clinical trial for patients with RP.
Rod-cone therapy is independent of the gene and focused on treating the rods in the eye while keeping the cones intact. The rods of the retina die first (see light and dark).
Also investigations and studies are conducted in the world that do not specifically offer a solution for people suffering from Usher Syndrome, but that may be of significance for them in the future.
Solutions, therapies and medical aids for other disorders can in a later stage be applied to people suffering from Usher Syndrome as well.
There are many challenges in research into Usher syndrome. Researchers specifically focus on a methodology, a strategy and / or a specific Usher protein.
The proteins control all processes in our bodies. These proteins are built using codes that have been captured in the DNA. Due to a writing error in the DNA a protein can be produced incorrectly or not at all. Fixing this DNA error changes the production of the protein and so makes the disorder disappear or reduces the symptoms. This is the idea behind the genetic therapies that are now under development throughout the world.