Inherited retinal disorders
Inherited retinal disorders most commonly present from birth/early infancy to the second/third decades. Inherited retinal conditions now represent the commonest cause of severe visual loss in the working age population and the second commonest in childhood in the UK. Professor Michel Michaelides is a world leading expert in Inherited Retinal Disorders with over 150 peer-reviewed publications, 18 co-authored book chapters, and a lead investigator of multiple studies and trials.
They are a very variable group of conditions, which require specialist retinal expertise to establish an accurate timely diagnosis with appropriate examination and investigations, in order to provide reliable advice, information on prognosis and offer appropriate genetic counselling.
In many instances these disorders may be complicated by other eye conditions including cataract, glaucoma, macular oedema or choroidal neovascularisation – for which treatments are available.
The majority of inherited retinal conditions are isolated problems with no general health concerns, however some are associated with other disorders such as hearing loss or diabetes.
There are multiple avenues of research being explored including gene therapy, stem cell therapy, artificial vision and pharmacological approaches, with several on-going clinical trials and many more planned in the immediate future. There is cautious optimism that some of these will likely result in meaningful treatments.
Two of the most common inherited retinal conditions are retinitis pigmentosa and stargardt disease
Stargardt Disease (also know as Stargardt macular dystrophy or Fundus Flavimaculatus) is the most common inherited macular dystrophy. It has an autosomal recessive mode of inheritance.
Most people with Stargardt disease have slowly progressive central visual loss that begins in early teenage years. Stargardt disease may also present in adult life when the visual loss may be milder.
The faulty gene that causes Stargardt disease has been identified, and is called ABCA4. This gene is involved in recycling vitamin A in the retina. Vitamin A is an essential component of the light detecting ability of the retina.
Retinitis pigmentosa (RP) is the name given to a group of inherited diseases of the retina that all lead to a gradual progressive reduction in vision. RP affects approximately 1 in 3,500 to 4,000 people.
Difficulties with night vision and peripheral vision are the first things that are noticed. Later, reading vision (detailed vision) and colour vision are affected. The age at which symptoms start is variable and may vary with the different genetic types. The rate at which vision deteriorates is also variable but is generally very slow with changes occurring over years rather than months.
In approximately half of all cases (50 to 60%) there are other family members with RP. There are three main inheritance patterns, autosomal recessive, autosomal dominant and X-linked inheritance, depending on the genetic cause.