Genetic Conditions Associated with Macular Degeneration
Inherited conditions include:
Which are caused by the accumulation of drusen, yellow-white deposits, in the macular area. Drusen deposits usually appear in the first three decades of life, and become larger as a person ages. Decreased vision may not be noticed until the fourth decade, with vision varying between 6/9 and 6/24. If the drusen causes other complications in the retina, vision may decrease to 6/60.
Sorsby Macular Dystrophy
Which is a rare disorder in which new blood vessels grow under the fovea, resulting in fluid build-up in the macular, haemorrhage, and general wasting of other layers of tissue in the eye. Usually symptoms do not appear until after the age of 40. Drusen may also be present. People with this disorder may experience a rapid decrease in vision. The gene for this disorder has been identified as the TIMP3 gene, which is located on the long arm of Chromosome 22.
Pigment Pattern Dystrophy
Which describes a group of disorders that includes Butterfly shaped Pigment Dystrophy of the fovea, North Carolina Macular Dystrophy, Macro reticular (Spider) Dystrophy and Sjogren Reticular Pigment Epithelium Dystrophy. The macular changes in these patients can occur at any age, but usually first appear in childhood. Many patients do not experience symptoms and may have visual acuities in the 6/6 to 6/24 range. Some of the genes have gene identified for these disorders and are located on chromosome 6.