Overview
Genetic disorders are the most common reason for visual disability in childhood. Finding genes that cause these conditions has been highly successful, with major scientific benefits. This has created a need for genetic testing to support affected patients and families.
Prof Black and team have developed a national service for genetic testing for inherited retinal dystrophies that has been running since 2005. The service is free to patients, but when the team evaluated how it was working they found that access to the service was not equal.
An expert working-group confirmed the findings on inequality in 2008 and recommended that research should be done to work out the most effective way to provide care for families with genetic eye disorders. So the aims of this programme of research are to:
Develop a model for providing clinical services to families with inherited retinal dystrophy. The model is to be patient-led and based on evidence from interviews with patients and health professionals. The model can then be tested to find out how well it works in practice.
Study the potential of new DNA sequencing technology to change the way we find genetic faults. The team is looking at how well the new technology can identify people with faults in genes that we already know cause eye conditions and also how well it can discover new genes and genetic faults.
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Publications
- Ellingford, J. M. et al. Whole Genome Sequencing Increases Molecular Diagnostic Yield Compared with Current Diagnostic Testing for Inherited Retinal Disease. Ophthalmology 123, 1143–1150 (2016).
- Harrison, M. et al. Variation in healthcare services for specialist genetic testing and implications for planning genetic services: the example of inherited retinal dystrophy in the English NHS. Journal of Community Genetics 6, 157–165 (2015).
- Moosajee, M., Ramsden, S. C., Black, G. C. M., Seabra, M. C. & Webster, A. R. Clinical utility gene card for: choroideremia. Eur. J. Hum. Genet. 22, (2014).
- Gillespie, R. L., Hall, G. & Black, G. C. Genetic testing for inherited ocular disease: delivering on the promise at last? Clin. Experiment. Ophthalmol. 42, 65–77 (2014).
- Combs, R. et al. Understanding the impact of genetic testing for inherited retinal dystrophy. Eur. J. Hum. Genet. 21, 1209–1213 (2013).
- Ramsden, S. C. et al. A clinical molecular genetic service for United Kingdom families with choroideraemia. Eur J Med Genet 56, 432–438 (2013).
- Eden, M. et al. Valuing the benefits of genetic testing for retinitis pigmentosa: a pilot application of the contingent valuation method. Br J Ophthalmol 97, 1051–1056 (2013).
- Combs, R. et al. Understanding the expectations of patients with inherited retinal dystrophies. Br J Ophthalmol 97, 1057–1061 (2013).
- Davies, W. I. L. et al. Next-generation sequencing in health-care delivery: lessons from the functional analysis of rhodopsin. Genet. Med. 14, 891–899 (2012).
- O’Sullivan, J. et al. A paradigm shift in the delivery of services for diagnosis of inherited retinal disease. J. Med. Genet. 49, 322–326 (2012).
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Research update
The research programme has produced a number of important results, including
- Research published in the Journal of Community Genetics that reveals a stark variation in genetic testing services for inherited eye conditions in England.
- Developing a 180-gene test for inherited retinal dystrophy
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Scientific summary
Improving healthcare provision for patients with inherited retinal diseases: an evidence-based approach.
The identification of genes causing retinal dystrophies has been highly successful, shedding light on biochemical pathways critical to photoreceptor health. It has expanded the need for genetic testing to support management of affected patients and families.
Since 2005 Prof Black and team has provided a national service for genetic testing for inherited retinal dystrophies. It is free at the point of contact - funding is provided by Strategic Health Authorities and subject to local priority constraints. Their audit data show inequality of access to these services.
In 2008, an expert working group, led by Prof Tony Moore, reviewed clinical services for families with inherited eye diseases. The group identified variation in service provision across the UK. These observations support the recommendation that research be undertaken to examine the most effective model of care provision for families with genetic eye diseases.
The aims of this programme are:
- to develop a patient-led, evidenced-based model for providing genetic services to families with inherited retinal dystrophy. This requires interviews with patients and health professionals to create an optimum care model that can be tested within an exploratory trial to assess the acceptability and potential cost effectiveness of the model.
- Current techniques for mutation detection are ineffective for conditions of high heterogeneity such as retinitis pigmentosa. So-called 'next generation' sequencers now open up exciting possibilities that will accelerate our ability to undertake genome resequencing for mutation detection. We will evaluate this technology using testing for adRP as a test case.