Causes of Genetic Eye Disease
It can result from a change in the normal genetic code (DNA sequence). Most genetic disorders are caused by a combination of genetic and environmental factors, but a large proportion is also due to mutations in single genes or chromosomal abnormalities. The resultant disease can affect the eyes alone, but can also involve other parts of the body (forming a syndrome).
Genetic eye disease includes congenital (present at birth) eye malformations (microphthalmia [small abnormal eyes], anophthalmia [no eyes] and ocular coloboma [cleft in the eyeball]), congenital cataracts, congenital glaucoma, inherited retinal degenerations, optic atrophy and certain types of strabismus with a family history.
Common diseases such as refractive error e.g. myopia (short-sightedness), glaucoma and age-related macular degeneration also have a genetic component together with environmental influences.
Therapies and Treatments
It is important to consult a specialist in eye genetics to make an accurate timely diagnosis as they have expertise in identifying genetic eye conditions through the appropriate examination and investigations, in order to provide reliable advice, information on prognosis and offer appropriate genetic counselling. There are many novel therapies on the horizon for genetic eye disease and knowing one’s genetic mutation can help gain access to new research and treatments.
Genetic testing can be used to find out whether a person is carrying a specific altered gene (genetic mutation) that causes a particular eye condition.
It may be carried out for a number of reasons, including to:
- diagnose a person with a genetic condition
- help work out the chances of a person developing a particular condition
- determine whether a person is a carrier of a certain genetic mutation that could be inherited by any children they have
Dr Mariya Moosajee routinely performs genetic testing for patients to address the cause, inheritance, chance of passing it to any children and recruitment into clinical trials. She uses a number of tests including screening a panel of 450 known eye disease causing genes and whole genome sequencing, which involves reading all 3 billion letters of your genetic code.
What does genetic testing involve?
Genetic testing usually involves having a sample of your blood taken, DNA is extracted from your blood cells. It can be tested to find out whether you’re carrying a certain mutation and are at risk of developing a particular genetic condition.
Depending on the genetic mutation being tested for, it can take months for the results of the genetic tests to become available. This is because the laboratory has to gather information to help them interpret what’s been found. You can also receive genetic counselling to provides support, information and advice about genetic conditions.