Abstract
Purpose: :
Previous studies have shown significant associations of variants in complement factor H (CFH) and ARMS2 genes and age-related macular degeneration (AMD). The correlation with specific phenotypes of early AMD has yet to be established. This study aims to assess the potential relation between drusen as clinical signs of early AMD and AMD-associated genetic variants in a large German cohort.
Methods: :
We identified 406 patients with early AMD who participated in the first follow-up of the Muenster Aging and Retina Study (MARS). We used standardized fundus photographs and the Rotterdam classification for diagnosis. Six binary (0-1) drusen features were assessed: drusen number (</> 20); confluence (</> 10%); biggest drusen size (</> 175 microm.); area covered by drusen (</> 10%); predominant type of drusen (</> 175 microm.); presence of soft, indistinct drusen (no/yes). A "drusen severity score" was calculated based on the sum of the individual values for each feature (range 0 to 6 points). The score values were compared with variants in CFH (SNP rs1061170) and ARMS2 (SNP rs10490924) using uni- and multivariate statistics (chi-square test, linear regression).
Results: :
Risk variants in the CFH (p = 0.002) and ARMS2 gene (p < 0.001) were significantly related to the occurrence of higher Rotterdam stages. Each of the six drusen features was independently associated with the risk variants in CFH and ARMS2, respectively (each p < 0.039). The mean "drusen severity score" was lowest for non-carriers of both CFH and ARMS2 risk variants, and highest for patients who were homozygous for both. This association persisted after adjustment for age and gender (adjusted mean score 1.42 vs. 4.38, p < 0.001).
Conclusions: :
The present study showed significant associations between AMD-associated variants in CFH and ARMS2 genes and various drusen features. These findings demonstrate that genetic parameters are, apart from the general development of AMD, related to the specific appearance and severity of drusen in early AMD.
Keywords: age-related macular degeneration • drusen • genetics