Leber Congenital Amaurosis Health Article

Definition

Leber congenital amaurosis (LCA) is a group of autosomal recessive-inherited eye disorders which lead to blindness at birth or within the first few years of life. Other manifestations of the disease may include hearing loss, mental retardation and decreased physical coordination.

Description

Vision is an important and complex sense by which the qualities of an object, such as color, shape, and size, are perceived through the detection of light. For proper vision, a critical series of biological steps must occur; if any of the steps in the process is abnormal, visual impairment or blindness may occur.

The process of vision begins with light that bounces off an object and passes through the outer coverings and lens of the eye and projects onto a layer of cells at the back of the eye called the retina. The retina contains two kinds of specialized cells types, called the rods and cones, that are responsible for sensing visual stimuli. When rods and cones are stimulated by light, impulses are conducted through the optic nerve to a region in the back of the brain known as the occipital lobe. The occipital lobe contains the visual cortex, the area of the brain that processes visual stimuli and integrates signals sent by the retina to obtain a composite image of an object.

Leber congenital amaurosis (LCA) is a term for a group of inherited conditions in which the rod and cone receptors in the retina are defective or missing. Without the proper function of these specialized cells, light cannot be sensed normally.

LCA is often referred to by other names, such as: congenital absence of the rods and cones, congenital retinal blindness, congenital retinitis pigmentosa, Leber congenital tapetoretinal degeneration, or Leber congenital tapetoretinal dysplasia. The disorder was first described by the German ophthalmologist, Theodor Leber, in 1869, who subsequently showed that it was an inherited defect. Although similarly named, LCA should not be confused with another disorder of sight, Leber optic atrophy, that was also discovered by Theodor Leber.