Fragile vision: Until recently there was no way of telling who was predisposed to AMD
An at-home genetic test that predicts the risk of macular degeneration, a leading cause of blindness, could motivate thousands of people to take important measures to help preserve their eyesight.
A saliva sample is sent off for analysis to assesses a person's genetic risk of developing Age-Related Macular Degeneration (AMD), the most common cause of blindness in the UK, which affects more than half-amillion people.
Depending on the result, the patient can then undertake lifestyle and dietary changes that have been shown to significantly reduce the risk of developing the disease.
AMD occurs when the macula - the central part of the retina that sends fine, detailed images to the brain - begins to break down. Despite medication, the disease is progressive, with half of all sufferers being registered as partially sighted or blind.
Unfortunately, it has few early symptoms, and by the time it is diagnosed there is often already permanent visual damage.
While 75 to 85 per cent of AMD cases can be traced to genes inherited by family members, until recently there was no way of determining who might carry those genes.
Thanks to the new test, which has been shown to be 100 per cent accurate at detecting high-risk genes for AMD, such an assessment is now possible.
The at-home test, which costs £399, consists of a small test-tube where a saliva sample can be deposited. The test-tube is then sealed and sent in a prepaid envelope to a lab for genetic testing and analysis.
'The test assesses six genes and eight genetic markers that have been linked to a raised risk of AMD,' says Tim Clove, chief executive of Optegra, a company specialising in ophthalmology who have launched the test.
'By assessing these genes, we can give a personalised interpretation of genetic risk.'
The patient receives a full report within 14 days and, if deemed to be at risk of developing the disease, they will be contacted by a genetic counsellor for a free consultation.
The test, says Tim Clove, means that anyone who is concerned about a family member or themselves can be analysed for AMD risk.
'This test is especially useful if you have relatives with AMD. Then you can discover if you have inherited high-risk genes and take action. You can lose weight, stop smoking and boost the fruit and vegetable content of your diet - all factors that can reduce AMD risk significantly,' says Tim.
'Vitally, you'll be able to go for regular scans that can pick up any signs of AMD at the earliest stage, when drug treatments are more effective and loss of vision can be significantly reduced.'
Professor Andrew Lotery, professor of ophthalmology specialising in macular disease at Southampton General Hospital, welcomes the test but warns about its accuracy.
'Genetic testing for macular disease is a useful advance,' he says. 'An Australian colleague found he was predisposed to MD because of a genetic test. He is now taking extra vitamins to reduce his risk, so it can be very motivating.
'However, some people can have high-risk genes for macular degeneration and never develop the disease,' he adds. 'In these cases, genetic testing would cause unnecessary worry.'
In those deemed high-risk, lifestyle changes might still not be enough to prevent blindness.
'You could eat a healthier diet or follow a better lifestyle but it still might not be enough to prevent AMD,' says Cathy Yelf, of the Macular Disease Society.
'This kind of test will be much more useful once we have gene therapies or stemcell treatments that could do something definite in response to the results.'
• For further information about the test, visit www.optegra.com.
Easier diabetes checks are here tooChecking blood glucose levels is an integral part of diabetes management. And now monitoring is simpler thanks to an innovative digital meter, launched by Roche.
The Accu-Check Mobile is the first monitor not to use test strips. Instead, the device contains a cassette that allows users to carry out up to 50 tests on a continuous
tape. The Mobile is larger than previous monitors - about the size of mobile phone - but features an integrated fingerpricker so no additional kit is required.
Test cassettes are available on prescription.
Accu-Chek Mobile Blood Glucose Monitor is available from www.boots.com at £49.99.
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