What is it?
Choroideremia is a rare inherited cause of severe sight loss in men. Symptoms start in childhood with trouble seeing at night and eventually lead to complete blindness by around the age of 40.
Choroideremia is caused by faults in the gene known as CHM. This leads to the slow loss of cells from the light-sensitive part of the eye (the retina) and from blood vessel layer (the choroid) that supplies food and oxygen to the retina.
Women can carry the choroideremia gene but are not usually affected by any symptoms.
Boys with choroideremia develop night blindness in childhood. This progresses to tunnel vision and eventually to blindness 20 to 30 years after symptoms began.
There is no current treatment for choroideremia but gene therapy research is looking promising.
Gene therapy for choroideremia was made possible by the Tommy Salisbury Choroideremia Fund at Fight for Sight. The funds meant that Professor Miguel Seabra and team at Imperial College London were able to work out what REP1 (the CHM protein) does.
Professor Robert MacLaren at Oxford’s Nuffield Laboratory of Ophthalmology then led the team that developed the ground-breaking gene therapy to replace faulty CHM with a healthy version. The world’s first clinical trial of the therapy reported promising results in The Lancet in 2014. Some participants showed some improvement in vision. The phase 2 clinical trial led by this same team has had funding approved and is due to start in late 2015.
Tommy Salisbury was four years old when he was diagnosed with choroideremia, a rare inherited condition.
Tommy’s mum, Emma, was a carrier of the condition as was his grandmother it was then passed on to Tommy. The condition had also affected Emma’s grandfather and he lost his sight at the age of 48.
Following Tommy’s diagnosis and after realising that there was no cure for the condition, the family, with the help of Fight for Sight, created the Tommy Salisbury Choroideremia Fund. Tommy’s mum, Emma and grandmother. Dot spearheaded this ambitious fundraising mission to help raise funds to support research specifically into the condition.
As a direct result the fund greatly increased the research capability of Professor Miguel Seabra, at Imperial College London. Professor Seabra’s fifteen year research project put a particular focus on gene therapy trials. This work was the crucial stepping stone, allowing a pioneering clinical trial to begin in 2011, led by Professor Robert MacLaren, Professor of Ophthalmology at the University of Oxford.
Emma said: “Once you start looking into a condition you realise that funding is needed for medical research. Without eye research, you’re never ever going to find treatment. It’s so important that there is this extra funding from families like us.”
The results from the phase one clinical trial were published in The Lancet (January 2014) and following this NightstaRx Ltd was formed to help take the therapy to clinic. The company has attracted £17 million investment from Wellcome Trust’s subsidiary Syncona and in November 2015 closed a $35 million funding round led by New Enterprise Associates (NEA).
Currently the condition affects Tommy’s night vision and he said: “I just hope in the future that the trial will become available for me and I can have the treatment done - hopefully it will stop my eyesight from deteriorating further.”
You could play an important part in eye research by being a participant in clinical research study that may benefit many people. You could even help shape clinical research by becoming more actively involved and having a say. Patients, carer, or anyone with an interest can help.
What are clinical trials
Clinical trials are research studies that find out if a medical strategy, treatment, or device is safe and effective for humans. They are a key research tool for improving medical knowledge and patient care. The people who carry out research are mostly the same doctors and healthcare professionals who treat people. Their aim is to find better ways of treating patients and keeping people healthy.
Here are some ways to find out about research projects and clinical trials that you can get involved in.
UK Clinical Trials Gateway
The UK Clinical Trials Gateway run by the National Institute for Health Research (NIHR) provides easy to understand information about clinical research trials running in the UK, and gives to a large range of information about these trials. It is designed to enable patients and clinicians to locate and contact trials of interest. Visit their website and select the eye condition that you are interested in.
NIHR Clinical Research Network Portfolio
The NIHR Clinical Research Network Portfolio is a database of high-quality clinical research studies in England, Northern Ireland, Scotland and Wales. Within this the Ophthalmology Specialty Group supports a national portfolio of research studies in ophthalmology and the vision sciences. See their website for details.
If you wish to join a trial it is always best to discuss this with your doctor or clinical team first.
Last updated August 2015
Approved by Professor Robert MacLaren, Nuffield Laboratory of Ophthalmology, University of Oxford