North Carolina macular dystrophy (NCMD, MCDR1) is a congenital autosomal dominant trait that appears to be completely penetrant. It is generally nonprogressive. The ophthalmoscopic findings are highly variable and are always much more dramatic than one would predict from the relatively good visual acuity level, which ranges from 20/20 to 20/400 (median, 20/60). Patients may have only a few drusen in the central macular region (grade I), confluent drusen confined to the central macular region (grade II), or a severe macular coloboma/staphyloma (grade III) involving 3 to 4 disc areas of the central macular region. Choroidal neovascular membranes develop in some patients. Color vision is normal. Electrophysiologic studies are also normal (summary by Small, 1998). Genetic Heterogeneity of Retinal Macular Dystrophy MCDR2 (608051) is caused by mutation in the PROM1 gene (604365) on chromosome 4p15. MCDR3 (608850) is caused by a duplication on chromosome 5p15. MCDR4 (619977) is caused by mutation in the CLEC3B gene (187520) on chromosome 3p21. MCDR5 (see 613660) is caused by mutation in the CDHR1 gene (609502) on chromosome 10q23. See MAPPING for possible additional loci for MCDR.

Drusen are extracellular deposits that accumulate below the retinal pigment epithelium on Bruch membrane. They appear as slightly raised, yellow subretinal nodules randomly scattered in the macula. 'Drusen' is the plural for 'Druse,' German for 'nodule' or 'crystal' (summary by Bok, 2002, Boon et al., 2008).

Butterfly-shaped pigmentary macular dystrophy is an autosomal dominant eye disease characterized by bilateral accumulation of pigment in the macular area that resembles the wings of a butterfly (summary by van Lith-Verhoeven et al., 2003). For a general phenotypic description and a discussion of genetic heterogeneity of patterned macular dystrophy, see 169150.

Age-related macular degeneration-3 (ARMD3) is characterized by numerous small round yellow lesions visible at the temporal edge of the macula. Larger, less distinct yellow areas near the center of the macula are also observed, which represent areas of pigment epithelial detachment (Stone et al., 2004). For a phenotypic description and a discussion of genetic heterogeneity of age-related macular degeneration, see 603075.

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).

Reticular pigmentary retinal dystrophy is a form of patterned dystrophy (see MDPT1, 169150) characterized by a reticular pattern of pigmentation that likely appears in infancy and may be fully developed at age 15 years. Indirect funduscopy has shown that the condition is bilateral and symmetric and that the pigmentary deposits are localized below the neuroepithelium, very likely in the pigment epithelium. The reticulum extends from the macula in all directions, sparing the midperiphery and periphery. Visual acuity is unaffected or only minimally affected in advanced stages. Retinal function testing is normal, although the electrooculogram and dark adaptation can be at the lower limit of normal values (summary by Schauwvlieghe et al., 2013).

Age-related macular degeneration (ARMD) is a multifactorial disorder of the central retina that is the most prevalent cause of progressive vision loss in the developed world. As in other chronic age-related diseases, most cases result from interplay between multiple environmental and genetic factors, with a resultant spectrum of phenotypes. In rare cases, ARMD may manifest early, but there is an exponential rise in prevalence after the age of 60 years (summary by Pras et al., 2015). For a phenotypic description and a discussion of genetic heterogeneity of age-related macular degeneration (ARMD), see 603075.

Macular dystrophies are inherited retinal dystrophies in which various forms of deposits, pigmentary changes, and atrophic lesions are observed in the macula lutea, the cone-rich region of the central retina. Vitelliform macular dystrophies (VMDs) form a subset of macular dystrophies characterized by round yellow deposits, usually at the center of the macula and containing lipofuscin, a chemically heterogeneous pigment visualized by autofluorescence imaging of the fundus (summary by Manes et al., 2013). Vitelliform macular dystrophy-4 is characterized by late-onset moderate visual impairment, small satellite drusen-like lesions in the foveal area, preservation of retinal pigment epithelium (RPE) reflectivity, deposits above the RPE between the ellipsoid and outer segment interdigitation lines on spectral-domain optical coherence tomography (SD-OCT), and normal or borderline results on electrooculography (EOG) (Meunier et al., 2014). In most families with VMD4 caused by compound heterozygous or homozygous mutations in IMPG1, asymptomatic heterozygous carriers have been found to have fundus changes (Manes et al., 2013; Brandl et al., 2017). Brandl et al. (2017) examined patients VMD4, caused by mutation in the IMPG1 gene, and VMD5 (616152), caused by mutation in the IMPG2 gene, and observed strikingly similar phenotypic characteristics. They noted that retinal lesions progressed in consecutive stages, with the initial development of a single vitelliform lesion in the central macula, with detachment of the neurosensory retina and hyperreflective material located above a preserved Bruch membrane/RPE on SD-OCT. Next, resorption of the hyperreflective material occurs, leaving behind a dome-shaped, optically empty cavity; alternatively, the foveal cavity formed by retinal detachment may become successively filled with material. Finally, there is collapse of the cavity with central retinal atrophy and loss of RPE, resulting in the most pronounced loss of visual acuity. The authors also noted that symptoms tended to be more severe in those with IMPG1 mutations. For a discussion of genetic heterogeneity of vitelliform macular dystrophy, see VMD1 (153840).

Usher syndrome type 1M (USH1M) is characterized by prelingual sensorineural hearing loss, vestibular dysfunction, and retinitis pigmentosa (Ahmed et al., 2018). For a general phenotypic description and discussion of genetic heterogeneity of Usher syndrome, see USH1 (276900).