Pattern Dystrophy

Published on 10/05/2015 by admin

Filed under Opthalmology

Last modified 22/04/2025

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12.3

Pattern Dystrophy

Introduction:

Pattern dystrophies encompass a group of phenotypically similar macular disorders that are inheritable and share a common genetic defect in the PRPH2 gene. They are usually inherited in an autosomal dominant pattern.

Clinical Features:

There are dark, yellow, and/or orange pigment disturbances at the level of the RPE, leading to characteristic patterns of deposition in the central macula, which are often vitelliform-like (Fig. 12.3.1). There is a lifetime risk up to 18% of developing secondary choroidal neovascularization. The clinical features are usually symmetric, but there can be heterogeneity between eyes (Fig. 12.3.2).

Figure 12.3.1 Color fundus photograph shows a yellowish, circular vitelliform-like lesion within the central macula.

Figure 12.3.2 Color fundus photograph of fellow eye from Figure 12.3.1, shows numerous clumps of pigment within the central macula. This likely represents a collapsed vitelliform lesion.

A disturbance at the level of the RPE is the rule. In the setting of a vitelliform-like lesion, there is moderately reflective material underneath or within the RPE layer (Fig. 12.3.3). Below this are highly reflective, drusen-like deposits. In the absence of a vitelliform-like lesion, there are typically highly reflective, drusen-like deposits within the RPE layer (Fig. 12.3.4). There can be a hyporeflective, empty space overlying the pigmentary disturbance. The significance of this fluid-like compartment is not clearly understood, but it usually does not represent the presence of choroidal neovascularization and would not be expected to be VEGF-responsive.

Figure 12.3.3 OCT (corresponding to Figure 12.3.1) shows moderately reflective material that appears to split the RPE layer. There are also highly reflective, drusen-like deposits underlying this area.

Figure 12.3.4 OCT (corresponding to Figure 12.3.2) shows highly reflective, drusen-like deposits corresponding to the pigment disturbances seen in the color photograph.