Apolipoprotein E Gene Affects Macular Degeneration
Meta-analysis finds risk/benefit associations between E2 and E4 alleles
MONDAY, Nov. 6 (HealthDay News) -- Certain apolipoprotein E polymorphisms are associated with a greater risk of age-related macular degeneration, while others have protective effects against the disease, researchers report in the Nov. 1 issue of the American Journal of Epidemiology.
Ammarin Thakkinstian, Ph.D., of the University of Newcastle in New South Wales, Australia, and colleagues analyzed 10 studies in whites and Asians from 1966 through 2005 that reported apolipoprotein E polymorphism links to age-related macular degeneration.
In whites, the frequencies of E2 and E4 alleles were about 8 percent and 15 percent, respectively. Although results for the E2 allele were not significant, the findings suggest that there may be up to a 20 percent increase in macular degeneration risk. The E4 allele results were statistically significant and at least one E4 allele may confer up to a 38 percent decrease in risk for age-related macular degeneration.
"There appears to be a differential effect of the E2 and E4 alleles on the risk of age-related macular degeneration, although the possibility of survivor bias needs to be ruled out more definitively," the authors conclude.