From this month, IMO’s Genetics Department will be offering pioneering genetic counselling for age-related macular degeneration (AMD) to all those who wish to undergo a new genetic test to find out their risk of developing the disorder.
From a saliva sample, the individual’s DNA will be analysed to detect genetic predisposition to AMD by studying the markers of the main genes associated with the disorder (CFH, CFB, C3 and ARMS2). The test results will enable the patient to be categorised into one of four risk groups; very low, low, moderate or high, in order to determine whether it is necessary to start a process of prevention or early treatment.
Patients categorised as moderate or high-risk can be between two and five times more likely to develop AMD than a person who does not have any risk markers. The information will be extremely useful for predicting the clinical diagnosis of a disorder that is difficult to treat and alerting asymptomatic individuals that they are in a medium-/high-risk group. In this event, IMO’s geneticists and retina specialists can help patients interpret and evaluate the results and propose an individualised action plan that involves, among other measures, arranging a schedule of eye check-ups, initiating preventative treatment (e.g. vitamin supplements), eliminating factors that could speed up the onset of the disorder or aggravate it, such as smoking, and encouraging patients to follow a healthy diet that is rich in natural antioxidants and omega 3.
Patients will also be informed of the latest progress in understanding and treating the disorder and given access, when available, to new gene therapies that are currently in the research phase. The information gleaned from the new test will be of great value, since approximately 70% of the risk of developing AMD is associated with genetic factors. To date, some twenty or so genes related to the disorder have been identified, although the test, developed by the company, Secugen, only focuses on the four that have been studied most, which is sufficient to ensure that the results are completely reliable.
As well as genetic predisposition, other risk factors also exist, such as smoking, the individual’s degree of pigmentation, UV radiation, diet and certain health issues, in particular, hypertension. As a result, the main beneficiaries of the test, in addition to patients who are in the early stages of the disorder, are their relatives and other risk groups, such as smokers and people with obesity, hypertension and diabetes. In fact, the high incidence of AMD – in Spain, more than 10% of the population over the age of 65 are affected – justifies extending the test to anyone from the age of 40. Moreover, the current trend shows that AMD is increasingly affecting an older percentage of the population due to greater life expectancy. It is predicted that by 2020, 7.5 million people over the age of 65 will be suffering from AMD in the world.
AMD is the leading cause of severe vision loss in elderly people in developed countries, affecting the macula, which is located in the middle of the retina. As it develops, central vision is reduced, making it difficult to carry out tasks that require seeing fine detail, such as reading, dialling phone numbers, driving or recognising faces.
The disorder is age-related. It affects the over 50s and especially people over the age of 65. Although often symptomless in its early stages, the condition can become highly disabling. Early diagnosis is, therefore, essential. There are two forms of the disorder: dry, the most common, involving atrophy of the macula, and wet, which occurs in about 15% of patients, results in abnormal growth of blood vessels under the macula and abruptly affects vision.
Currently, treatment to control the development of wet AMD is carried out with intravitreal antiangiogenic drugs (which slow blood vessel growth), while effective treatment for the dry form has yet to be found, although the administration of antioxidant complexes can slow it down.