This study will examine whether certain polymorphisms (small gene variances) predispose people to develop age-related macular degeneration (AMD). This eye condition affects people over 50 years of age and can cause permanent loss of central vision. The study will examine and compare the frequency of polymorphisms in patients with AMD to that of individuals without AMD. This information will help identify genetic risk factors for the AMD and may lead to the development of more effective treatments.

Patients 50 years of age and older with advanced AMD and healthy normal volunteers may be eligible for this study. All participants will provide an eye health history and will have 10 milliliters (2 teaspoons) of blood drawn from an arm vein. The DNA in the blood will be isolated and tested for certain genes that other research indicates are important in aging and age-related diseases. The normal and polymorphic gene sequences will be identified and compared in patients with AMD and control subjects to determine if any of the polymorphisms are related to development of AMD.

In addition, control subjects will have a routine eye examination, including dilation of the pupils for examination of the back of the eye.

Age-related macular degeneration (AMD) is the leading cause of irreversible severe central visual loss older than 50 in the world. The incidence and progression of all the features of AMD are known to increase significantly with age. Approximately 10% of people 66 to 74 years of age will have findings of AMD, and the prevalence increases to approximately 30% in people 75 to 85 years of age. Recently in a large study with three racially similar populations of 14,752 participants from North America, Europe and Australia, the prevalence of AMD is present in 0.2% of the combined population aged 55 to 64 years, rising to 13% of the population older than 85 years.

Epidemiological studies of candidate gene association and linkage disequilibrium suggest that AMD has a significant genetic component. Current evidence supports the hypothesis that variance of genes involved in DNA repair, oxidative stress and inflammation play a role in aging and age-related diseases. Recently studies have documented the association between polymorphisms in complement factors (CF), oxidative stress, apolipoprotein E (ApoE), mitochondria and chaperone proteins genes and AMD. Single nucleotide polymorphism (SNP) in ApoE, ApoE or C2/BF may protect AMD. On the other hand, SNP in CFH, AMRS2/HtrA-1 or CX3CR1 gene may increase AMD risk. In this study, we would like to test whether the variations of biologically plausible genes (or the modifying genes) listed above are differentially distributed in AMD patients and normal populations. To this end, we choose genes that are believed to play a crucial role in the aging process and will analyze the frequency of SNPs specifically within the coding frames of biologically plausible genes responsible for aging and age-related diseases.

Our aim will be to compare the allelic frequencies of candidate genes listed above in cohorts with AMD to the frequency in normal control subjects without AMD. With this study we hope to identify genetic risk factors that could have functional implications for understanding and treating AMD.

• Tuo J, Smith BC, Bojanowski CM, Meleth AD, Gery I, Csaky KG, Chew EY, Chan CC. The involvement of sequence variation and expression of CX3CR1 in the pathogenesis of age-related macular degeneration. FASEB J. 2004 Aug;18(11):1297-9. Epub 2004 Jun 18.
• Tuo J, Ning B, Bojanowski CM, Lin ZN, Ross RJ, Reed GF, Shen D, Jiao X, Zhou M, Chew EY, Kadlubar FF, Chan CC. Synergic effect of polymorphisms in ERCC6 5' flanking region and complement factor H on age-related macular degeneration predisposition. Proc Natl Acad Sci U S A. 2006 Jun 13;103(24):9256-61. Epub 2006 Jun 5.
• Tuo J, Ross RJ, Reed GF, Yan Q, Wang JJ, Bojanowski CM, Chew EY, Feng X, Olsen TW, Ferris FL 3rd, Mitchell P, Chan CC. The HtrA1 Promoter Polymorphism, Smoking, and Age-related Macular Degeneration in Multiple Case-control Samples. Ophthalmology. 2008 Nov;115(11):1891-8. Epub 2008 Aug 21.

• INCLUSION CRITERIA:

AMD Patients (cases):

1. Diagnosis of advanced AMD defined by geographic atrophy and/or choroidal neovascularization with drusen of any size in at least one eye.
2. Age 50 years or older.
3. If sample previously donated in a different study, the patient has given their permission to use their sample (i.e. marked appropriate selection in the informed consent).

Control Patients (controls):

1. Absence of drusen or no more than 5 drusen less than 63 microns, absence of other diagnostic criteria for AMD.
2. Agrees to undergo study examinations.

EXCLUSION CRITERIA:

1. Presence of retinal disease involving the photoreceptors and/or outer retinal layers other than AMD loss such as high myopia, retinal dystrophies, central serous retinopathy, vein occlusion, diabetic retinopathy and uveitis or similar outer retinal diseases that have been present prior to the age of 50.
2. Opacities of the ocular media, limitations of papillary dilation or other problems sufficient to preclude adequate stereo fundus photography. These conditions include occluded pupils due to synechiae, cataracts, vitreous haze and opacities due to ocular diseases.