Age related macular degeneration in monozygotic twins and their spouses inIceland

Purpose: To examine the importance of genetic factors in age-related macula r degeneration by using a twin study to compare the concordance of age-rela ted macular degeneration in monozygotic twin pairs and their spouses. Methods: This was a prospective study that included 50 twin pairs and 47 sp ouses. Zygosity was determined by genetic laboratory testing. Macular findi ngs were graded based on the grading system used by the Macular Photocoagul ation Study Group and the International ARM Epidemiological Study Group. Results: The concordance of age-related macular degeneration was 90% in mon ozygotic twin pairs which significantly exceeded that of twin/spouse pairs (70.2%); p=0.0279. In the nine pairs that were concordant, fundus appearanc e and visual impairment were similar. Environmental factors and medical his tory were essentially the same in the twin pairs. Conclusion: The statistically significant higher concordance of age-related macular degeneration in monozygotic twins compared to their spouses strong ly suggests the importance of genetic factors.