Cone-rod dystrophy

Also known as: cone-rod degeneration, cone-rod retinal dystrophy, CORD, CRD, retinal cone-rod dystrophy, tapetoretinal degeneration

Definition

Genetics Home Reference

Cone-rod dystrophy is a group of related eye disorders that causes vision loss, which becomes more severe over time. These disorders affect the retina, which is the layer of light-sensitive tissue at the back of the eye. In people with cone-rod dystrophy, vision loss occurs as the light-sensing cells of the retina gradually deteriorate.

The first signs and symptoms of cone-rod dystrophy, which often occur in childhood, are usually decreased sharpness of vision (visual acuity) and increased sensitivity to light (photophobia). These features are typically followed by impaired color vision (dyschromatopsia), blind spots (scotomas) in the center of the visual field, and partial side (peripheral) vision loss. Over time, affected individuals develop night blindness and a worsening of their peripheral vision, which can limit independent mobility. Decreasing visual acuity makes reading increasingly difficult and most affected individuals are legally blind by mid-adulthood. As the condition progresses, individuals may develop involuntary eye movements (nystagmus).

There are more than 30 types of cone-rod dystrophy, which are distinguished by their genetic cause and their pattern of inheritance: autosomal recessive, autosomal dominant, and X-linked. Additionally, cone-rod dystrophy can occur alone without any other signs and symptoms or it can occur as part of a syndrome that affects multiple parts of the body.

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Orphanet

Cone rod dystrophies (CRDs) are inherited retinal dystrophies that belong to the group of pigmentary retinopathies.

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Classification

Symptoms

Medical Term Other Names Description
Retinal dystrophy Retinal dystrophy is an abnormality of the retina associated with a hereditary process. Retinal dystrophies are defined by their predominantly monogenic inheritance and they are frequently associated with loss or dysfunction of photoreceptor cells as a primary or secondary event.
Cone/cone-rod dystrophy Cone-rod retinal dystrophy, Cone rod dystrophy, Cone dystrophy [more]
Retinopathy Noninflammatory retina disease Any noninflammatory disease of the retina. This nonspecific term is retained here because of its wide use in the literature, but if possible new annotations should indicate the precise type of retinal abnormality.
Photophobia Extreme sensitivity of the eyes to light, Photodysphoria, Light hypersensitivity [more] Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light.
Nyctalopia Night-blindness, Difficulties with night vision, Poor night vision [more] Inability to see well at night or in poor light.
Dyschromatopsia Color blindness A form of colorblindness in which only two of the three fundamental colors can be distinguished due to a lack of one of the retinal cone pigments.
Reduced visual acuity Central visual loss, Central blurring of vision, Poor visual acuity, Decreased visual acuity, Decreased central vision [more]
Blindness Legal blindness Blindness is the condition of lacking visual perception due to physiological or neurological factors.
Pigmentary retinopathy Retinal pigmentary degeneration, Pigmentary retinal deposits, Retinal pigment clumping [more] An abnormality of the retina characterized by pigment deposition. It is typically associated with migration and proliferation of macrophages or retinal pigment epithelial cells into the retina; melanin from these cells causes the pigmentary changes. Pigmentary retinopathy is a common final pathway of many retinal conditions and is often associated with visual loss.
Scotoma Blind spot Scotoma refers to an area or island of loss or impairment of visual acuity surrounded by a field of normal or relatively well-preserved vision.

Other Classifiers and IDs