Reticular Dystrophy Of Retinal Pigment Epithelium

Description

Reticular dystrophy is a disorder of protean manifestations occurring in the retinal pigment epithelium (RPE) with little or no involvement of the neurosensory retina. The disorder may be detected at an early age and may be slowly progressive, but the prognosis for visual acuity is good. Abnormalities of dark adaptation and nyctalopia may develop with time. Electrophysiologic testing may show a normal electroretinogram (ERG), subnormal electrooculogram (EOG), and subnormal results of dark adaptation studies (summary by Kingham et al., 1978).

Clinical Features

Hsieh et al. (1977) reported 2 sibs and their mother with patterned dystrophies of the RPE: the 21-year-old sister exhibited butterfly-shaped pigment dystrophy, her 23-year-old brother showed macroreticular dystrophy, and their 51-year-old mother had 'probable' reticular dystrophy. The authors noted that this family linked together several entities that had been considered separate phenotypes.

Kingham et al. (1978) described 4 affected individuals over 3 generations of a family with reticular dystrophy of the RPE. The proband was a 24-year-old woman who presented with 'eye strain' and normal visual acuity. Fundus examination revealed a reticular pattern of pigment clumping in the RPE, like a 'fishnet with knots,' that was most pronounced around the macula but extended around the optic disc and was present nasal to the disc as well. ERG findings were normal, but dark adaptation showed decreased rod and cone amplitudes, and EOG showed reduced light peak/dark trough values. The proband's 20-year-old sister had no ocular complaints, but examination showed a similar fishnet-with-knots pattern, and the sister's 2-year-old daughter had macular pigment stippling. The sisters' 51-year-old father, who had decreased visual acuity and difficulty with night vision, showed irregular patchy loss of pigmentation in the macula and posterior pole of both eyes; fluorescein angiography revealed loss of underlying choriocapillaris as well, and remnants of a reticular pattern were seen in the midperiphery. The father's brother had no ocular complaints and normal examination except for reduced cone and rod amplitudes on dark adaptation testing.

McGimpsey and Rankin (2007) reported an 11-year-old girl who was asymptomatic but had an unusual fundus appearance involving a dark clump of pigment at each fovea, with a bilateral symmetric reticular pattern of RPE pigment clumping like a 'fishnet with knots.' ERGs were within normal limits.

Inheritance

Kingham et al. (1978) reviewed published reports of reticular dystrophy and concluded that it is an autosomal dominant disease. Recessive inheritance has been suggested by others (see 267800).