Genetics and ARMD
=================

* Ian M. MacDonald
* Matthew A. Lines

*   © 2004 Canadian Medical Association or its licensors

Thank you for Erica Weir's Public Health article on age-related macular degeneration (ARMD).1 The term for this condition sounds like an apology for our inability to identify a better cause, but in fact genetics plays a large role in a person's predisposition to macular degeneration. Several genes may be associated with macular degeneration, including *ABCA4*, *VMD2*, *EFEMP1*, *TIMP3*,2 *ELOVL4*3 and *CRX*.4 However, a search for mutations in these genes in patients with a diagnosis of ARMD has been disappointing, except in the case of *ABCA4*. Patients who carry mutations in both *ABCA4* alleles have an autosomal recessive disorder called Stargardt disease.5 Allikmets6 has shown a significantly higher incidence of mutations in the *ABCA4* gene among patients with ARMD than in a control population. These mutations may contribute to the higher risk of vision loss from ARMD among first-degree relatives of patients with the condition, estimated at 4 times the risk for the general population.7

How can ARMD be prevented? As mentioned by Weir, stopping smoking and eating a healthy diet are both important. In particular, eating fish at least twice a week reduces the risk.8 Fish is an excellent source of omega-3 fatty acids, in particular docosahexaenoic acid, the predominant highly unsaturated fatty acid of the retina. With people now living into their 80s, a healthy lifestyle and a healthy diet are important not only for general well- being but also for good vision.

**Ian M. MacDonald Matthew A. Lines** Ocular Genetics Laboratory University of Alberta Edmonton, Alta.

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