Inherited Retinal Dystrophies

There is often, but not always, a family history of affected relatives. Inheritance can be in several forms such as autosomal dominant where most generations have an affected individual, autosomal recessive where the condition can skip generations, X-linked where the condition affects mostly males with females as carriers, and sporadic, where new mutations can arise. If parents are related, the risk of inheriting a condition can be increased.

Symptoms often start in childhood or early adulthood and can include night blindness, difficulty with reading, tunnel vision, light sensitivity and squints. Sometimes other parts of the body may also be affected e.g. hearing loss.

Some of the more common inherited retinal dystrophies are retinitis pigmentosa (rod-cone dystrophy), Leber’s Congenital Amaurosis, Stargardt macular dystrophy (ABCA4 retinopathy), cone-rod dystrophy, and Best disease. The prevalence of inherited retinal dystrophies in Australia is approximately 1 in 2000 persons.

During your eye examination, you will usually undergo scans and tests to help confirm the diagnosis. These include:

• Optical Coherence Tomography (OCT)
• Retinal photography including fundus autofluorescence.
• Visual field testing (perimetry).

Electrophysiology testing, which is a test to determine the function of the light sensitive cells can also be organised, as can genetic testing.

Unfortunately, there remain no proven treatments for inherited retinal dystrophies in general. Gene therapy is promising, and there is now a licenced gene therapy, Luxturna (Voretigene neparvovec-rzyl) for a very rare form of inherited retinal dystrophy that affects mainly young children. It does not work for other forms of inherited retinal dystrophy, but new gene therapies continue to be investigated.