Genetic testing for inherited retinal disease and age-related macular degeneration
Professor Michel Michaelides is the inherited retinal disease (IRD) eye doctor here at Clinica London. He also looks after patients with retinal medical problems such as age-related macular degeneration, diabetic retinopathy and maculopathy and high myopia with macular oedema. The current advances being made with gene testing for inherited retinal disease are not matched for complex diseases such as age-related macular degeneration. Advances in gene sequence technology and reduced gene testing costs will affect this area of research in the future.
At present, there is no evidence that molecular genetic testing for age-related macular degeneration is of any clinical value and the recommendation of the American Academy of Ophthalmology is to avoid routine genetic testing for age-related macular degeneration, as well as some complex ocular disease. However, as we begin to further understand the interplay between genetic variants and environmental risk factors in response to therapy, it is possible that molecular genetic data will be useful in identifying patients at increased risk of disease progression and eventually influence the choice of therapy. There is much research to be carried out in this area, and clinical trials will need to demonstrate that clinical outcomes are benefited by genotype information before routine testing becomes available.
Inherited retinal diseases, however, affect 1 in 3500 individuals in North America and Europe and are now an important cause of blindness in children and adults of working age, and for that reason alone this becomes of significant visual importance as patients who cannot see, cannot fully contribute socially and economically, and yet have the ability to do so. Many patients are now requesting molecular testing as they are increasingly well informed about clinical trials and new therapies. Many of the trials are using gene therapy and require knowledge of the specific gene mutation causing the disease. There are gene therapy trials already underway for specific forms of
- Leber congenital amaurosis
- Achromatopsia, choroideremia
- X-linked retinitis pigmentosa
- Usher syndrome type 1
- Stargardt’s disease
- Juvenile x-linked retinoschisis.
If you want to find out more about Professor Michaelides work, please consult his website or book to have a consultation with him here at Clinica London. He is a leading player in many of the current gene therapy trials.
Recruitment to these trials depends on there being a sufficient number of patients with these rare disorders who know their specific disease mutation. Insurance companies and other funding agencies are reluctant to fund molecular genetic testing unless there is clear evidence that the results of testing will accurately predict the clinical status of the patient and affect clinical management.
Patients whose clinical situation does not fulfil such criteria will still be able to obtain testing as part of a research study or will need to self-pay. Fortunately, the costs of molecular investigations are decreasing, and it is likely that molecular diagnosis will become more widely available. Currently, the cost of molecular investigation has been a significant barrier to testing. We are on the cusp of an exciting new era of effective treatments for patients with IRD/inherited retinal diseases, and molecular diagnosis will become an essential part of that.
Currently, we do not have enough ophthalmologists who can interpret the results of molecular testing and feedback these results to their patients and families. However, at Clinica London, we and the patients are extremely lucky to have Professor Michel Michaelides, who is a leading world expert on inherited retinal disease and can advise you on whether you require molecular testing and whether trials are currently being carried out in the area of your problem. He works closely with his clinical genetic colleagues. He is a leader in this exciting and rapidly changing field.