Explore the overlapping challenges of inherited retinal diseases
The genetic heterogeneity of inherited retinal diseases can make it challenging to reach a specific diagnosis. A single gene may even be associated with multiple phenotypes1-3
*Mapped genetic loci without an identified gene, as of 2019.4
©2021 American Academy of Ophthalmology. Reproduced with permission.
BBS=Bardet-Biedl syndrome; CD=cone dystrophy; CSNB=congenital stationary night blindness; CRD=cone-rod dystrophy; JBS=Joubert syndrome; LCA=Leber congenital amaurosis; NPHP=nephronophthisis; RP=retinitis pigmentosa; SLS=Sjögren-Larsson syndrome; USH=Usher syndrome.
Genetic testing further supports clinical findings and has become the standard for reaching a more precise diagnosis. A more accurate diagnosis helps inform the best course of action for future medical management1,15
Read case studies about overlapping gene variantsThe American Academy of Ophthalmology recommends genetic testing for most patients with a suspected inherited retinal disease.
Inherited retinal diseases: signs, symptoms, and prevalence
Disclaimer: All prevalence rates are global estimates and may vary across regions.
Signs & symptoms may include
- Nyctalopia (earliest symptom)
- Blind spots merge to produce tunnel vision over time
- Loss of central vision over time
Age of onset
- Presents in childhood or adulthood
Estimated prevalence
- Up to 1 in 3,000
Signs & symptoms may include
- Males experience earlier and more severe symptoms than females
- Rapid progression of vision loss, resulting in legal blindness
- Early nyctalopia
Age of onset
- Early onset
Estimated prevalence
- 5%–15% diagnosed with RP
Signs & symptoms may include
- Partial or total hearing loss and vision loss over time
- Loss of night vision occurs first
- Blind spots merge to produce tunnel vision over time
- Three different clinical types (I, II, and III) with variable symptom severity and presentation
Age of onset
- Presents at birth (Usher syndrome type I, type II), or by adolescence or adulthood (Usher syndrome type III)
Estimated prevalence
- Up to 1 in 6,000
Signs & symptoms may include
- Slow, progressive loss of central vision
- Nyctalopia
- Color blindness
Age of onset
- Presents in late childhood to early adulthood
Estimated prevalence
- Up to 1 in 8,000
Signs & symptoms may include
- Decreased visual acuity
- Photophobia
- Loss of color vision
- Scotomas
- Loss of peripheral vision
- Legal blindness by mid-adulthood
Age of onset
- Presents in childhood
Estimated prevalence
- Up to 1 in 30,000
Signs & symptoms may include
- Partial or total absence of color vision
- Can only see black, white, and shades of gray
- Photophobia
- Nystagmus
- Reduced visual acuity
- Hyperopia
Age of onset
- Presents at birth or early infancy
Estimated prevalence
- Up to 1 in 30,000
Signs & symptoms may include
- Vision loss (at birth to early infancy)
- Photophobia
- Nystagmus
- Hyperopia
- Keratoconus
- Franceschetti’s oculo-digital sign (eye poking, pressing, and rubbing)
Age of onset
- Usually presents at infancy
Estimated prevalence
- Up to 1 in 33,000
Signs & symptoms may include
- Progressive atrophy of the outer retina and inner choroid
- Nyctalopia in early childhood
- Progressive loss of peripheral visual field and visual acuity
- All individuals will develop blindness, most commonly in late adulthood
Age of onset
- Usually presents in early childhood
Estimated prevalence
- Up to 1 in 50,000
Signs & symptoms may include
- Nyctalopia
- Blind spots merge to produce tunnel vision over time
- Blurred central vision
- Legally blind by adolescence or early adulthood
- Renal malformations
- Obesity
- Postaxial polydactyly
- Hypogonadism
- Developmental delays
Age of onset
- Ocular symptoms present in first decade of life
Estimated prevalence
- Up to 1 in 160,000
- While BBS is one of the rarest inherited retinal diseases, its prevalence may be higher in some geographic regions
Going beyond the clinical signs and symptoms
Clinical signs and symptoms may raise suspicion that your patient has an inherited retinal disease. Your patient may express additional concerns during their exam, such as19,20:
- Worry about inherited retinal disease being passed down to others in their family
- Challenges in daily activities such as driving, shopping, or reading
- Issues with mobility such as crossing the street or walking up stairs
- Difficulty working or finding new employment
- Problems interacting with family and friends
- Overwhelming fear about going blind
- Feelings of frustration or anxiety
Family history alone doesn’t tell the full story
Obtaining a thorough family history can help assess your patient’s risk or identify a likely pattern of inheritance. Although the majority of patients who have no known family history have autosomal recessive disease, some may have dominant disease due to a de novo pathogenic variant. Others may have a dominant disease exhibiting incomplete penetrance. And still there are those who may have no known family history of X-linked disease.1,21,22
of patients with retinitis pigmentosa have no known family history of retinal disease22
Early testing matters
Early genetic testing may allow you to detect genetic
variants responsible for inherited retinal diseases sooner.23,24 This enables you
and your patients’ care teams to create a more comprehensive plan for the
future.20,25
New answers may help your patients move forward in their lives from career and family
planning to speaking with family members who may also benefit from genetic
testing.20,25

If you suspect an inherited retinal disease26…
- Establish clinical diagnosis of an inherited retinal disease
- Assess visual function and plan visual rehabilitation
- Confirm the genetic diagnosis and genetic management, and partner with a genetic counselor or genetic specialist
- Monitor disease progression and plan for therapeutic interventions

Taking these proactive steps including testing your patients’ genes for an inherited retinal disease can help them get closer to the answers they need.