1. Therapy Areas
  2. Ophthalmology
  3. Inherited retinal dystrophies (IRDs)
  4. Clinical diagnosis of an IRD

Clinical diagnosis of an IRD

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Establishing a complete diagnosis offers patients more information about their IRD.1

For patients living with an inherited retinal dystrophy (IRD) (such as RP, LCA) a complete diagnosis requires:

Clinical examination

clinical examination and genetic diagnosis

Genetic diagnosis

 

Medical and family history1,2

Do other family members have similar symptoms?

Assessment of signs and symptoms1,2

Spectral domain OCT (retinal structure/integrity) FST* (light sensitivity)
ERG* (rod/cone electrophysiology)
Physical signs such as nystagmus

Exclusion of non-ocular syndromic symptoms3

Are other organs affected?
This could indicate a syndromic disorder such as Usher syndrome (which can also affect hearing)

Visual acuity1,2

Fundus examination1,2†

 

 

*Test should be requested through referral to the appropriate centre if not available.
†in younger patients, the fundus may appear normal.

Royal College of Ophthalmologists Guidance on Genomic Services4:

In line with the drive towards a Genomic Medicine Service, it is important that testing is offered to anyone who is eligible and would benefit.

Each examination must include a genetic diagnosis to avoid delays in decision-making.

 

 

There are >270 genes associated with an IRD4,5
A genetic test refines and completes their diagnosis.1

Patients want genetic insight into their disease.6
A genetic test = knowing more.

 

Treatment options such as gene therapy
need a genetic diagnosis.7,8

A genetic test with segregation analysis.1,9

  • Screening of parents or relatives to determine mode of inheritance, i.e. biallelic mutations.1
  • This test can be ordered by any physician with a suspected IRD patient or consider referring your patient to a specialist who can perform or order a test.
 

 

At the foundation of an accurate IRD diagnosis is a genetic test

The following case studies highlight the important role genetic testing plays to achieve a final diagnosis.

 

Chart to illustrate one male and one female patient case study to demonstrate the importance of a genetic test, including images of fundus examination.

Chart illustrating two different patient ocular examination results with the same diagnosis; both patients have poor vision and uncontrolled eye movements

 

Chart illustrating two different patient electrophysiology examination results with the same diagnosis; both patients have photoreceptor defects

 

Chart illustrating two patient case studies to demonstrate the importance of a fundus examination

Three images showing patient fundus abnormalities, one from fundus imaging, two from optical coherence tomography

Fundus imaging

Three images showing patient fundus abnormalities, one from fundus imaging, two from optical coherence tomography

Irregular ellipsoid zone band (OCT)

Three images showing patient fundus abnormalities, one from fundus imaging, two from optical coherence tomography

Irregular ellipsoid zone band (OCT; arrowhead)

 

Patient has fundus abnormalities

 

 

""

Differential diagnosis:

Reduced VA, colour defects, nystagmus and reduced ERG are common across a range of IRDs including achromatopsia, Leber congenital amaurosis and retinitis pigmentosa.

Without a genetic test the patient cannot receive a definitive and complete diagnosis.3

 

Chart confirming the genetic diagnosis of one of the patient case studies: mutation in CEP290

 

Chart confirming the final diagnoses of the two patient case studies: one early retinitis pigmentosa, one congenital stationary night blindness type 1

 

Chart illustrating the importance of performing a genetic test early in the patient pathway

Referral network

Three centres in the UK provide all genetic testing within ophthalmology4:

 

London North GLH led by Great Ormond Street Hospital for Children NHS Foundation Trust

 

 

North West GLH led by Manchester University NHS Foundation Trust

 

 

West Midlands, Oxford and Wessex GLH

 

 

The Genomic Test Directory defines a series of clinical indications for which genomic tests are available including inherited retinal disorders (retinal dystrophies and vitreoretinal disorders).

 

Centralised funding from NHS England means that molecular genetic testing should be both possible and affordable.

 

The drive towards a national Genomic Medicine Service means that testing is offered to anyone who is eligible and who would benefit.

In the UK, a genetic test* can be ordered from one of the three Genomic Laboratory Hubs. The Hubs will be able to advise on how to request a test for a particular patient, and comprehensive information and instructions can be found on their individual websites.

*Genetic testing should be accompanied by patient consent and full genetic counselling.

Give patients with IRDs the opportunity for a complete diagnosis with a clinical and genetic test.1

ERG, electroretinography; FST, full-field stimulus test; GLH, Genomic Laboratory Hub; IRD, inherited retinal dystrophy; LCA, Leber congenital amaurosis; NHS, National Health Service; OCT, optical coherence tomography; RP, retinitis pigmentosa; VA, visual acuity.

References

  1. American Academy of Ophthalmology®, IRD Clinical Statement. 2016. https://www.aao.org/clinical-statement/recommendations-on-clinical-assessment-of-patients (Accessed October 2022).
  2. Chung D et al. Am J Ophthalmol 2019;199:58–70.
  3. Sahel JA Cold Spring Harb Perspect Biol 2015;5(2):a017111.
  4. The Royal College of Ophthalmologists Genomic Services Guide April 2020. https://www.rcophth.ac.uk/wp-content/uploads/2021/01/College-News-FOCUS_April2020.pdf (Accessed October 2022).
  5. RetNet. https://sph.uth.edu/retnet/sum-dis.htm (Accessed October 2022).
  6. Willis TA et al. Br J Ophthalmol 2013;97(9):1148–1154.
  7. Russell S et al. The Lancet 2017;390(10097):849–860.
  8. Novartis Pharmaceuticals UK Ltd. Luxturna®(voretigene neparvovec) Summary of Product Characteristics.
  9. Moosajee M et al. Eur J Hum Genet 2014;22(4):e1–e4.
  10. Di Ioro V et al. Genes 2017;8:280–297.
  11. Pieh C et al. Br J Ophthalmol 2008;92:236–240.
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UK | October 2022 | 236125
Ophthalmology
Article

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