Genetics, along with age, diet and smoking can influence the risk of advanced AMD. In 2013, seven new genes linked to AMD were discovered by an international consortium that included Casey's Macular Degeneration Center. The team also confirmed 12 genes identified in previous studies. Supported by the National Eye Institute (NEI), this is the largest genome-wide study for AMD to date.
The 19 regions linked to AMD involve a variety of biological functions, including the regulation of the immune system, maintenance of cell structures, growth and permeability of blood vessels, lipid metabolism and atherosclerosis.
The two gene variants most strongly connected to AMD are complement factor H gene (CFH) and ARMS2. The CFH gene is located on chromosome 1 and is part of the complement system, which is involved in inflammation. Although ARMS2 is also strongly associated with AMD, its function is not entirely known.
Gene discoveries help investigators understand underlying causes of the disease and develop new methods of prevention and treatment. They can also help identify who is likey to develop AMD and how they may respond to certain treatments.
The Role of Genes and Lifestyle Behaviors in Progression to Advanced AMD
Casey scientists, in collaboration with other investigators, have discovered that carriers of the CFH and ARMS2 gene variants are more likely to progress to the advanced form of the disease. The study also reported that lifestyle factors, such as smoking and body weight, increased the risk. When genetic information is available, it may in certain cases supplement other information, such as retinal findings and personal factors in determining when progression from early to advanced AMD is likely to occur.
Genes and AMD Therapies
Genetic makeup may also play a role in how patients respond to various treatments for AMD. Casey investigators found that an individual's response to the AREDS formulation of antioxidants and zinc may be affected by variations in the CFH and LOC387715 genes. However, studies by others show possible differences in response to various AMD treatments depending on the presence or absence of certain genetic variants.
Routine genetic screening for AMD is not recommended at this time. Additional research is needed to replicate and add to the findings thus far. Furthermore, more effective preventive measures are not yet available.
At this time, preventive measures like nutritional supplements can potentially benefit all patients at high risk of progressing to advanced AMD, regardless of their genetic makeup.