A twin study of age-related macular degeneration.
OBJECTIVE
To determine the importance of genetic factors in age-related macular degeneration by using a twin study to compare the concordance of age-related macular degeneration in monozygotic and dizygotic twin pairs.


METHODS
We prospectively examined 134 consecutive twin pairs and two triplet sets for age-related macular degeneration. The zygosity was determined by genetic laboratory tests.


RESULTS
The concordance of age-related macular degeneration was 100% (25 of 25) in monozygotic and 42% (five of 12) in dizygotic twin pairs. The other twins or triplets had no macular changes of age-related macular degeneration.


CONCLUSIONS
The statistically significant higher concordance of age-related macular degeneration in monozygotic than in dizygotic twin pairs and the clinical heterogeneity of age-related macular degeneration strongly suggest the importance of genetic and nongenetic factors, respectively, in age-related macular degeneration.
Division of Ophthalmology, Cleveland Clinic Foundation, OH 44195, USA.
S M
SM
Meyers
T
T
Greene
F A
FA
Gutman
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D004200:Diseases in Twins; D005260:Female; D005654:Fundus Oculi; D006801:Humans; D008268:Macular Degeneration / Q000209:etiology* / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010857:Pigment Epithelium of Eye / Q000473:pathology; D011446:Prospective Studies; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic