AMD: How gene variants can predict your risk of developing the disease

Gene variantsGene variants can predict whether or not a person is likely to develop age-related macular degeneration (AMD), a study has shown. But, when routine genetic testing can cost a patient several hundred dollars, how beneficial is it to detect AMD through genetic analysis?

The study

Research, performed by a team at Harvard Medical School, suggests that between 46 and 71 per cent of AMD’s overall severity is caused by genetic factors, as opposed to environment and lifestyle effects.

The study examined 840 twins aged between 86 and 96. Within the group researchers recorded 331 participants with no signs of AMD, 241 with early signs, 162 with mid-stage AMD, and 103 in the late stage.

By comparing the rates of AMD progression between non-identical and identical twins it was shown that there was a strong correlation between genetic backgrounds and the sight-threatening eye disease. This was possible as identical twins share a closer genetic background and within this sub-group there was a higher amount of twin sets both with AMD.

However, the study has not allowed scientists to isolate which genes contribute to the development of AMD. Furthermore it doesn’t show which genes are responsible for reacting poorly to the currently used treatments of Lucentis, Avastin or Eylea.

The genetic test

Currently a macula risk genetic test exists; unfortunately this routine test costs hundreds of dollars. When the price of said test is so high, and neglects to take into account other factors like lifestyle and environment, is it truly beneficial to the patient?

As the research has shown AMD is primarily an inherited disease, making a DNA test an obvious choice for those with relatives affected by the condition. However, the test does not take into account the current condition of the subject’s eyesight which may have been damaged by smoking, sunlight, or one of the other many causes of AMD.

The fast and accurate test for AMD

The MPS II macular pigment screener reads a patient’s macula within just 90 seconds, making testing for AMD fast and simples. The accurate readings given by the MPS II will reflect the current condition of the patient’s eye, taking into account genetics, environment, habits, and other factors to establish their risk of developing AMD. By having regular screenings, which can simply occur during a routine visit to an optometrist, the patient will be given a clear understanding of how to keep their eyesight in good condition.

Additionally the MPS II is an excellently cost-effective device, paying for itself over time. For example, if the device costs your practice $9,000 (£6000) and you charge $30 (£20) for a routine eye test then it would only take 300 patients to cover the machine’s cost. This makes financial sense for both your patients and the practice itself, in comparison to the macula genetic risk test.

The treatments

Whilst there are treatments for AMD, as well as medications which can slow progression like the AREDs formula, there is currently no cure. Scientific advancement, on the other hand, is rapidly looking into new ways to treat AMD sufferers.

Implantable telescope: A recent development was the introduction of an implantable telescope treatment which can improve eyesight. During a clinical trial the implant improved 60% of the trialled patients by three lines or more on the Snellen chart after two years. This ophthalmic surgery became available to the public earlier this year although this also has a heavy price tag, costing around $15,000 (excluding surgery and rehabilitation charges).

Stem cell treatments: Soon Japan will begin researching stem cell treatments in an effort to cure AMD, being the first in the world to green light the trials. However, stem cell research is a pioneering field and it will take years to develop a cure, and even then it may not be widely available due to controversy surrounding stem cell treatment.

Prevention: Along with medication there are simple and effective ways to ensure that you don’t succumb to the condition. These include being a non-smoker, regular exercise, and a diet rich in omega-3 and low in glycaemic index.

Further information

To find out more about the MPS II macular screening device visit the ophthalmic pages on the Elektron Technology website.

If you’d like to know more about preventing AMD please visit the AMD Alliance website.

[Picture credit: NHS Wales]

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