Your patient affected by inherited sight loss may have passed this information to you because they are considering genetic testing and genetic counselling. We have produced this information to support you in discussing choices with your patient and making appropriate referrals.
Potential benefits of a genetic test result:
- Confirmation of a specific diagnosis, which may clarify prognosis for vision loss and reveal potential for non-ophthalmic symptoms requiring specialist management.1
- Confirmation of inheritance pattern; choices for the patient and their family around family planning and further testing.
- Access to gene-specific clinical trials and treatments; a number of gene replacement and other molecular therapies are currently in trial, including UK centres. In 2020, the first gene therapy for inherited retinal disease was made available on the NHS.2
Limitations
In around one third of cases, testing will not return a genetic diagnosis, as some genes and mutations have yet to be identified and characterised. Research participation opportunities may be available to those patients with unidentified genes.
For many genes, there is no gene-specific treatment in the development pipeline, which may cause disappointment. However, gene-agnostic treatments such as cell therapies are now reaching clinical testing. Retina UK provides regular research updates.
Where possible, genetic testing should always be accompanied by or followed up with genetic counselling so that patients have an opportunity to discuss issues and options and receive a detailed explanation of their result.
In England, genomic testing in ophthalmology is now nationally commissioned through the Genomic Laboratory Hubs. NHS genetic testing for inherited retinal dystrophies now includes whole genome sequencing; consent is via the national Records of Discussion form.
How to refer: GPs (General Practitioners)
Please refer your patient with inherited sight loss to local ophthalmology or to a Ophthalmic genetics clinic. Unaffected relatives should be referred to clinical genetics.
How to refer: Ophthalmologists
Please draw blood and request the appropriate test if possible3, and/or refer on to the nearest Genetics specialist.
Further reading
- Royal College of Ophthalmologists Genomics Services Guidance
- Royal College of Ophthalmologists Focus article, April 2020
- Méjécase C, Malka S, Guan Z, Slater A, Arno G, Moosajee M. Practical guide to genetic screening for inherited eye diseases. Ther Adv Ophthalmol. 2020 Sep 22;12:2515841420954592. doi: 10.1177/2515841420954592. PMID: 33015543; PMCID: PMC7513416.
[1] Lenassi, E., Clayton-Smith, J., Douzgou, S. et al. Clinical utility of genetic testing in 201 preschool children with inherited eye disorders. Genet Med 22, 745–751 (2020). https://doi.org/10.1038/s41436-019-0722-8
[2] https://retinauk.org.uk/general-news/first-patient-receives-ground-breaking-treatment/
[3] www.england.nhs.uk/publication/national-genomic-test-directories