Inherited Retinal Disease
Inherited retinal diseases (also called inherited retinal dystrophies, or IRDs) are a group of rare eye disorders caused by an inherited gene mutation and can result in vision loss or blindness. It is however, a common cause of blindness in children and adults of working age. It affects about 1 in 4000 of the population. These genetic mutations affect how the retina tissues are made, or the proteins that allow the tissues to function properly. About half of patients affected have no family history of the disease.
Gene identification has come a long way and is now an integral part in helping with the management and treatment of retinal dystrophies. This can often help in determining the full understanding of the disease mechanism, improved genetic counseling, and improved prospects for gene therapy treatment.
Some people with inherited retinal diseases, for instance those with retinitis pigmentosa (RP) or choroideremia (CHM), experience a gradual loss of vision, eventually leading to complete blindness. Others, with conditions like Leber congenital amaurosis (LCA), may be born with or experience vision loss in infancy or early childhood. The retina is a wonderful tool for the study of genetic disease for several reasons. Not only can a wide variety of phenotypes be directly visualized and documented photographically but their effects on the organ can be quantified by psychophysical measures (acuity, field, color contrast) and retinal electrophysiology (by which it is now possible to dissect the function of each retinal cell type individually). Since retinal dystrophies are slowly progressive and may not become visually handicapping until adult life, families with these conditions often become large enough for genetic linkage studies.