MedGen

Patterned dystrophies of the retinal pigment epithelium (RPE) refer to a heterogeneous group of macular disorders, characterized by an abnormal accumulation of lipofuscin in the RPE. The lipofuscin is most apparent in the macular area, and its distribution can show various sizes and shapes. High inter- and intrafamilial variability has been described, and retinitis pigmentosa (RP; see 268000)-like changes have sometimes been observed in association with patterned dystrophies (summary by Vaclavik et al., 2012). Three main varieties of patterned dystrophy of the RPE have been described: reticular ('fishnet-like') dystrophy (see 179840 and 267800), macroreticular ('spider-shaped') dystrophy, and butterfly-shaped pigment dystrophy of the fovea. Genetic Heterogeneity of Patterned Macular Dystrophy Also see MDPT2 (608970), caused by mutation in the CTNNA1 gene (116805) on chromosome 5q31; and MDPT3 (617111), caused by mutation in the MAPKAPK3 gene (602130) on chromosome 3p21. [from OMIM]

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.

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).

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. [from MedlinePlus Genetics]

Central areolar choroidal dystrophy-2 (CACD2) is a hereditary retinal disorder that principally affects the macula, often resulting in a well-defined area of atrophy of the retinal pigment epithelium (RPE) and choriocapillaris in the center of the macula. Dysfunction of macular photoreceptors usually leads to a decrease in visual acuity, generally occurring between the ages of 30 and 60 years (summary by Boon et al., 2009). For a discussion of genetic heterogeneity of central areolar choroidal dystrophy, see CACD1 (215500). [from OMIM]

A retinitis pigmentosa that has material basis in mutation in the PRPH2 gene on chromosome 6p21. [from MONDO]

This form of fleck retina disease (see 228980) is characterized by discrete uniform white dots over the entire fundus with greatest density in the midperiphery and no macular involvement. Night blindness occurs. Both autosomal dominant and autosomal recessive inheritance had been suggested (Krill and Folk, 1962; Krill, 1977). [from OMIM]