What are inherited retinal diseases?

What are inherited retinal diseases?

Inherited retinal diseases defined

Inherited retinal diseases are a group of rare eye disorders that can lead to serious vision impairment or loss. They are sometimes also referred to as inherited retinal dystrophies or disorders. These conditions can occur when one or more of your genes are not working properly.[1][2]

You are not alone

Approximately 1 in 2,000 people have inherited retinal diseases based on global estimates*[1]

*Prevalence may vary by region, locality or subpopulation.

What are genes and gene variants?


Genes can be considered the great blueprint for life. Genes are stored in nearly every cell of your body and contain DNA, also known as deoxyribonucleic acid, which carries instructions for how you look and everything that makes you unique. As the body’s instruction manual, genes tell parts of your body how to grow and function.[3][4]

Gene variants

A “gene variant” is a change in one or more of the DNA sequences that make up your genes. A change means something was added, missing, or replaced in the DNA sequence.[5][6]

Let’s take a closer look inside the eye:

Image showing a side view of an eye with light coming in from the left with cones and rods at the back of the eye

Family history alone doesn’t tell the full story

Family history can reveal a lot about inherited retinal diseases, but it’s just one of the pieces that genetic experts and eye specialists use[11] to try to solve the diagnosis puzzle.

Nearly 50%

of people with an inherited retinal disease called retinitis pigmentosa have no knowledge of previous family history.[12]

If you do not have any known family history but have been suspected of having an inherited retinal disease, it’s still important to ask your eye specialist about genetic testing or retesting.[13]

It’s hard to distinguish one inherited retinal disease from another

Overlapping symptoms can make diagnosing inherited retinal diseases challenging. Therefore, genetic testing has become the benchmark to uncover a genetic diagnosis for your vision loss or impairment.[14]

Each inherited retinal disease is different and can have one or more of these common symptoms:[15][16][17]

  • Difficulty seeing at night
  • Sensitivity to light
  • Blind spots
  • Uncontrolled eye movements
  • Loss of central and/or peripheral vision
  • Farsightedness
  • Colour blindness

There are many different types of inherited retinal diseases.[14] Some include:

Disclaimer: All prevalence rates are global estimates and may vary across regions.

Retinitis pigmentosa (RP)
  • RP is one of the most common inherited retinal diseases[18]
  • Symptoms may begin in childhood or adulthood[15]
  • Up to 1 in 3,000 people have RP worldwide[15][18]
  • Approximately 15% of RP can be inherited in an X-linked pattern and can result in X-linked retinitis pigmentosa (XLRP).[19] X-linked refers to the linkage to the X chromosome, one of the sex chromosomes in the human genome. This type of RP is typically more severe in males than females and can result in severe vision impairment or loss[20]
  • Approximately 30% to 40% of all RP patients have autosomal dominant RP (ADRP), and approximately 50% to 60% have autosomal recessive RP (ARRP), regardless of gender[21]
  • Variants in more than 100 genes are known to cause a form of retinitis pigmentosa that only affects the eyes[15]
  • Some symptoms include[15]:
    • Progressive vision loss
    • Difficulty seeing at night
    • Blind spots that progress into loss of peripheral vision
    • Loss of central vision over time, which makes it difficult to read, drive, or recognise faces
  • A systemic disease that also affects other organs[22]
  • There are 3 types of Usher syndrome (USH1, USH2, USH3)[22]
  • Hearing symptoms usually appear at birth in USH1 and USH2, while hearing loss symptoms usually appear by late childhood or adolescence in USH3. Vision loss appears in childhood in USH1, and usually in adolescence in USH2 and USH3[22]
  • Globally, up to 1 in 6,000 people have USH[22]
  • Variants in 10 genes are known to cause Usher syndrome[22]
  • Some symptoms include[22]:
    • Hearing loss
    • Loss of night vision, the first visual symptom
    • Blind spots that progress into loss of peripheral vision
  • There is differentiation between onset in childhood, early adulthood, and late adulthood, when the average age at onset of symptoms is approximately 55 years[23][24]
  • Up to 1 in 8,000 people have Stargardt disease worldwide[23]
  • Variants in 2 genes are known to cause Stargardt disease[23]
  • Some symptoms include:[25]
    • Loss of central vision over time
    • Night blindness
    • Colour blindness
    • Symptoms and progression vary widely
  • Symptoms usually begin during childhood and worsen over time[26]
  • Globally, up to 1 in 40,000 people have CRD[26]
  • Variants in more than 30 genes are known to cause cone-rod dystrophy[26]
  • Some symptoms include[26]:
    • Decreased sharpness of vision
    • Sensitivity to light
    • Problems recognising colours
    • Blind spots
    • Loss of peripheral vision over time
    • Blindness by mid-adulthood
  • Symptoms develop in the first few months of life[27]
  • Up to 1 in 30,000 people have achromatopsia worldwide[27]
  • Variants in 6 genes are known to cause achromatopsia[27]
  • Some symptoms include[27]:
    • Partial or total loss of colour vision
    • Can only see black, white and shades of grey
    • Increased sensitivity to light
    • Involuntary eye movements
    • Reduced sharpness of vision
    • Farsightedness, or less commonly, nearsightedness
  • Symptoms usually appear during infancy[28]
  • Up to 1 in 33,000 people have LCA worldwide[28]
  • Variants in at least 38 genes are known to cause Leber congenital amaurosis[28]
  • Some symptoms include[28]:
    • Night blindness
    • Vision loss at infancy
    • Increased sensitivity to light
    • Involuntary eye movements
    • Extreme farsightedness
    • Pupils not reacting normally to light
  • Symptoms usually begin in early childhood[29]
  • Up to 1 in 50,000 males have CHM worldwide[29]
  • More males are affected by CHM than females[29]
  • Variants in the CHM gene cause choroideraemia[29]
  • Some symptoms include[29]:
    • Night blindness in early childhood
    • Loss of peripheral vision
    • Less ability to see details over time
    • Blindness, most commonly in late adulthood
  • A systemic disease that also affects other organs
  • Symptoms begin early- to mid-childhood[30]
  • Up to 1 in 120,000 people have BBS, in North America and Europe[30]
    • While BBS is one of the rarest inherited diseases, its prevalence may be higher in some geographic regions
  • Variants in at least 26 genes are known to cause Bardet-Biedl syndrome[30]
  • Some symptoms include[30]:
    • Night vision loss
    • Blind spots that progress into loss of peripheral vision

    • Blurred central vision
    • Problems with kidneys and eyes
    • Weight gain
    • Born with extra fingers or toes
    • Learning problems
    • Developmental delays
More answers lie in our genes

While you can’t change what you inherit, you may find answers that can help put you in control of your future.[31][32]

Microscope icon
5 simple steps to test

Know what to expect before, during and after your genetic test or retest.


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