BEST1 Gene

Autosomal dominant vitreoretinochoroidopathy (ADVIRC) is a disorder that affects several parts of the eyes, including the clear gel that fills the eye (the vitreous), the light-sensitive tissue that lines the back of the eye (the retina), and the network of blood vessels within the retina (the choroid). The eye abnormalities in ADVIRC can lead to varying degrees of vision impairment, from mild reduction to complete loss, although some people with the condition have normal vision.

The signs and symptoms of ADVIRC vary, even among members of the same family. Many affected individuals have microcornea, in which the clear front covering of the eye (cornea) is small and abnormally curved. The area behind the cornea can also be abnormally small, which is described as a shallow anterior chamber. Individuals with ADVIRC can develop increased pressure in the eyes (glaucoma) or clouding of the lens of the eye (cataract). In addition, some people have breakdown (degeneration) of the vitreous or the choroid.

A characteristic feature of ADVIRC, visible with a special eye exam, is a circular band of excess coloring (hyperpigmentation) in the retina. This feature can help physicians diagnose the disorder. Affected individuals may also have white spots on the retina.

Retinitis pigmentosa is a group of related eye disorders that cause progressive vision loss. These disorders affect the retina, which is the layer of light-sensitive tissue at the back of the eye. In people with retinitis pigmentosa, vision loss occurs as the light-sensing cells of the retina gradually deteriorate.

The first sign of retinitis pigmentosa is usually a loss of night vision, which becomes apparent in childhood. Problems with night vision can make it difficult to navigate in low light. Later, the disease causes blind spots to develop in the side (peripheral) vision. Over time, these blind spots merge to produce tunnel vision. The disease progresses over years or decades to affect central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. In adulthood, many people with retinitis pigmentosa become legally blind.

The signs and symptoms of retinitis pigmentosa are most often limited to vision loss. When the disorder occurs by itself, it is described as nonsyndromic. Researchers have identified several major types of nonsyndromic retinitis pigmentosa, which are usually distinguished by their pattern of inheritance: autosomal dominant, autosomal recessive, or X-linked.

Less commonly, retinitis pigmentosa occurs as part of syndromes that affect other organs and tissues in the body. These forms of the disease are described as syndromic. The most common form of syndromic retinitis pigmentosa is Usher syndrome, which is characterized by the combination of vision loss and hearing loss beginning early in life. Retinitis pigmentosa is also a feature of several other genetic syndromes, including Bardet-Biedl syndrome; Refsum disease; and neuropathy, ataxia, and retinitis pigmentosa (NARP).