An AMD patient who was diagnosed late with the disorder regrets the delay, because she now has less vision in one eye

Early detection of AMD is the key to slowing down development and safeguarding vision. A new test can detect our genetic predisposition to the disorder from a single drop of saliva.

Two years ago, María Guasch, 61, discovered that the black spots that were obstructing her vision, when focusing on objects, were not as harmless as she first thought. "A black blot appeared with lots of white lights around it, but, as it didn’t hurt, I didn’t pay any attention to it," she explains. Her GP initially advised her to change her glasses, and a specialist even adjusted the lenses. When there was no improvement, she consulted another expert, who finally diagnosed her with age-related macular degeneration (AMD).

The patient, who manages a shop in Barcelona, now regrets not having paid more attention to the condition, because the delay in diagnosis has resulted in her having less vision in one of her eyes. Her story is clear proof of the importance of early treatment of the disorder, which is the leading cause of severe vision loss in the elderly in developed countries.

The Genetics Unit of the Instituto de Microcirugía Ocular in Barcelona has, since May, been offering patients pioneering genetic counselling for the disorder, which initially involves undergoing a simple test. From a sample of saliva, a DNA analysis is performed to detect whether the individual is genetically predisposed to developing the condition. The process involves studying the markers of the main genes associated with the disorder. AMD is a complex disease, in which genetic factors account for 70% of the risk and environmental factors 30%. It is caused by a gene combination that increases predisposition to developing the condition. To date, 19 genetic predisposition markers have been identified and many more are likely to exist. It is important to identify those that are essential for predisposition and protection, a field in which considerable work is being undertaken, according to Dr Roser González, the head of the Genetics Research Unit of IMO, who highlights the advantages of the new procedure.

The genetic test is extremely useful for predicting diagnosis and alerting asymptomatic individuals with medium to high risk. In this event, IMO’s geneticists and retina specialists can propose an individualised plan that involves arranging a schedule of eye check-ups, initiating preventative treatment (e.g. vitamin supplements) and eliminating factors that can speed up the onset of the disorder or aggravate it.. "Studying genetic markers enables us to categorise the patient into one of four risk groups on a probability scale from very low to high. In relative terms, an individual in the high-risk group is 4 or 5 times more likely to develop the condition than someone of low risk. The test is very important for patients in the very early stages and for their family members," explains Dr González. As well as genetic predisposition, other risk factors also exist, such as smoking, the individual’s degree of pigmentation, diet and certain health issues, in particular, hypertension.

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