MedGen

Cone-rod dystrophy (CORD) characteristically leads to early impairment of vision. An initial loss of color vision and of visual acuity is followed by nyctalopia (night blindness) and loss of peripheral visual fields. In extreme cases, these progressive symptoms are accompanied by widespread, advancing retinal pigmentation and chorioretinal atrophy of the central and peripheral retina (Moore, 1992). In many families, perhaps a majority, central and peripheral chorioretinal atrophy is not found (Tzekov, 1998). Genetic Heterogeneity of Autosomal Cone-Rod Dystrophy There are several other autosomal forms of CORD for which the molecular basis is known. CORD3 (604116) is caused by mutation in the ABCA4 gene (601691) on chromosome 1p22. CORD5 (600977) is caused by mutation in the PITPNM3 gene (608921) on chromosome 17p13. CORD6 (601777) is caused by mutation in the GUCY2D gene (600179) on chromosome 17p13.1. CORD9 (612775) is caused by mutation in the ADAM9 gene (602713) on chromosome 8p11. CORD10 (610283) is caused by mutation in the SEMA4A gene (607292) on chromosome 1q22. CORD11 (610381) is caused by mutation in the RAXL1 gene (610362) on chromosome 19p13. CORD12 (612657) is caused by mutation in the PROM1 gene (604365) on chromosome 4p15. CORD13 (608194) is caused by mutation in the RPGRIP1 gene (605446) on chromosome 14q11. CORD14 (see 602093) is caused by mutation in the GUCA1A gene (600364) on chromosome 6p21. CORD15 (613660) is caused by mutation in the CDHR1 gene (609502) on chromosome 10q23. CORD16 (614500) is caused by mutation in the C8ORF37 gene (614477) on chromosome 8q22. CORD18 (615374) is caused by mutation in the RAB28 gene (612994) on chromosome 4p15. CORD19 (615860) is caused by mutation in the TTLL5 gene (612268) on chromosome 14q24. CORD20 (615973) is caused by mutation in the POC1B gene (614784) on chromosome 12q21. CORD21 (616502) is caused by mutation in the DRAM2 gene (613360) on chromosome 1p13. CORD22 (619531) is caused by mutation in the TLCD3B gene (615175) on chromosome 16p11. CORD23 (see 613428) is caused by mutation in the C2ORF71 gene (PCARE; 613425) on chromosome 2p23. CORD24 (620342) is caused by mutation in the UNC119 gene (604011) on chromosome 17q11. A diagnosis of CORD was made in an individual with a mutation in the AIPL1 gene (604392.0004) on chromosome 17p13.1, as well as in an individual with a mutation in the UNC119 gene (604011.0001) on chromosome 17q11.2. Other mapped loci for autosomal CORD include CORD1 (600624) on chromosome 18q21.1-q21.3; CORD7 (603649) on chromosome 6q14; CORD8 (605549) on chromosome 1q12-q24; and CORD17 (615163) on chromosome 10q26. For a discussion of X-linked forms of cone-rod dystrophy, see CORDX1 (304020). [from OMIM]

Adult-onset foveomacular vitelliform dystrophy, also known as adult vitelliform macular dystrophy, adult-type foveomacular dystrophy, adult vitelliform macular degeneration, pseudovitelliform macular degeneration, and adult-onset foveomacular pigment epithelial dystrophy, is characterized by a solitary, oval, slightly elevated yellowish subretinal lesion of the fovea that is similar in appearance to the vitelliform or egg-yolk stage of Best disease (153700). Initially the yellow lesion may be present in only one eye. The size is generally one-third to one disc diameter, and small yellow flecks are seen in the paracentral lesion. Patients usually become symptomatic in the fourth or fifth decade of life with a protracted decrease of visual acuity and mild metamorphopsia. Electrooculographic testing reveals a normal or only slightly reduced Arden ratio, which is intensely abnormal in Best disease. The prognosis is optimistic, as most patients retain reading vision throughout life (Felbor et al., 1997; Yamaguchi et al., 2001). For a discussion of genetic heterogeneity of vitelliform macular dystrophy, see VMD1 (153840). [from OMIM]

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]

Congenital grouped pigmentation of the retina is a rare disorder characterized by a grouping together of round to oval spots of pigment in one or more quadrants of the retina, except for the macula (summary by Renardel de Lavalette et al., 1991). [from OMIM]

A visual anomaly in which images appear distorted. A grid of straight lines appears wavy and parts of the grid may appear blank. [from HPO]