The three loci where identified gene variants are found are designated:

Complement Factor H (CFH) on chromosome 1 at location 1q31.3
HTRA serine peptidase 1/Age Related Maculopathy Susceptibility 2 (HTRA1/ARMS2) on chromosome 10 at location 10q26
Complement Factor B/Complement Component 2 (CFB/CC2) on chromosome 6 at 6p21.3

Specific genes
Polymorphisms in genes for complement system proteins: Variation in the genes for the complement system proteins factor H (CFH), factor B (CFB) and factor 3 (C3), among others, are strongly associated with a persons risk for developing AMD. CFH is involved in inhibiting the inflammatory response. The mutation in CFH (Y402H) results in reduced ability of the protein to localise to and protect tissues such as the retina from complement overactivation. Absence of the complement factor H-related genes R3 and R1 protects against AMD. Two independent studies in 2007 showed a certain common mutation Arg80Gly in the C3 gene, which is a central protein of the complement system, is strongly associated with the occurrence of AMD. The authors of both papers consider their study to underscore the influence of the complement pathway in the pathogenesis of this disease. In two 2006 studies, another gene that has implications for the disease, called HTRA1 (encoding a secreted serine protease), was identified. Six mutations of the gene SERPING1 (Serpin Peptidase Inhibitor, Clade G (C1 Inhibitor), Member 1)  are associated with AMD. Mutations in this gene can also cause hereditary angioedema. Fibulin-5 mutation: Rare forms of the disease are caused by genetic defects in fibulin-5, in an autosomal dominant manner. In 2004, Stone et al.
Beckers nevus (also known as "Beckers melanosis", "Beckers pigmentary hamartoma", "nevoid melanosis", and "pigmented hairy epidermal nevus") is a benign skin disorder predominantly affecting males. : 687  The nevus can be present at birth, but more often shows up around puberty. It generally first appears as an irregular pigmentation (melanosis or hyperpigmentation) on the torso or upper arm (though other areas of the  body can be affected), and gradually enlarges irregularly, becoming thickened and often hairy (hypertrichosis). The nevus is due to an overgrowth of the epidermis, pigment cells (melanocytes), and hair follicles. This form of nevus was first documented in 1948 by American dermatologist Samuel William Becker (1894–1964). Clinical information
Medical knowledge and documentation of this disorder is poor, likely due to a combination of factors including recent discovery, low prevalence, and the more or less aesthetic nature of the effects of the skin disorder. Thus the pathophysiology of Beckers nevus remains unclear. While it is generally considered an acquired rather than congenital disorder, there exists at least one case report documenting what researchers claim is a congenital Beckers nevus with genetic association: a 16-month-old boy with a hyperpigmented lesion on his right shoulder whose father has a similar lesion on his right shoulder. Prevalence
The most extensive study to date, a 1981 survey of nearly 20,000 French males aged 17 to 26, served to disprove many commonly held beliefs about the disorder. In the French study, 100 subjects were found to have Beckers nevi, revealing a prevalence of 0.52%.