The pattern dystrophies are a group of disorders characterized by the development, typically in midlife, of various patterns of yellow, orange, or gray pigment deposition at the level of the RPE in the macular area. These dystrophies may be subdivided into 4 major patterns according to the distribution of pigment deposits: (1) adult-onset foveomacular vitelliform dystrophy (discussed earlier in this chapter), (2) butterfly-type pattern dystrophy (Fig 13-20), (3) reticular-type pattern dystrophy (Fig 13-21), and (4) fundus pulverulentus (coarse pigment mottling). Patients are often asymptomatic. The most common presenting symptom of the pattern dystrophies is diminished visual acuity or mild metamorphopsia. The risk of developing choroidal neovascularization is low, but geographic macular atrophy may eventually develop.
Figure 13-20 Butterfly-type pattern dystrophy. A, Color fundus photograph from a 56-year-old woman shows a typical yellow macular pigment pattern. B, Fluorescein angiography image shows blocked fluorescence of the pigment lesion itself and a rim of hyperfluorescence from surrounding RPE atrophy.
(Used with permission from Song M-K, Small KW. Macular dystrophies. In: Regillo CD, Brown GC, Flynn HW Jr, eds. Vitreoretinal Disease: The Essentials. New York: Thieme; 1999:297. © Thieme.)
Figure 13-21 Color fundus photographs show 2 examples of reticular-type pattern dystrophy, characterized by a “fishnet” pattern of yellowish-orange (A) or brown (B) pigment deposition in the posterior fundus.
(Courtesy of Mark W. Johnson, MD.)
The inheritance is often autosomal dominant, but other modes of inheritance have been observed, including autosomal recessive and mitochondrial. The majority of the cases of autosomal dominant pattern dystrophy have been associated with mutations in PRPH2, but other genes and conditions can give rise to similar phenotypes, including pseudoxanthoma elasticum and some mitochondrial disorders.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.