The combination of a certain genetic variation, along with inflammatory factors and smoking, significantly increases the risk of the vision disorder age-related macular degeneration, according to a study in the July 19 issue of Journal of the American Medical Association.
Age-related macular degeneration (AMD) is the most important cause of irreversible visual loss in the elderly of the Western world, according to background information in the article. It has long been recognized that hereditary factors play a role in AMD and there is increasing evidence that inflammation is an important disease mechanism. Recent case-control studies demonstrated an association between the complement factor H (CFH) gene, a regulator of the complement pathway, and AMD.
Dominiek D. G. Despriet, M.D., of the Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues hypothesized that the effect of this regulator gene may be particularly hazardous in persons in whom the complement cascade is activated. They assessed the association between the CFH gene and AMD and investigated the modifying effect of smoking, serum inflammatory markers, and genetic variation of C-reactive protein (CRP). The population-based study included 5,681 individuals age 55 years or older who were assessed for the gene mutation CFH Y402H. Information on smoking, serum inflammatory markers and CRP gene variation were assessed at baseline.
The frequency of CFH Y402H was 36.2 percent. At baseline, there were 2,062 persons (36.3 percent) with any type of AMD (prevalent cases), including 78 (1.4 percent) with late AMD. During an average follow-up of 8 years, 1,649 (35.5 percent) of 4,642 participants progressed to a higher stage of AMD (new cases), including 93 (5.6 percent) who developed late AMD.